diff --git a/.buildkite/pipelines/es_serverless/verify_es_serverless_image.yml b/.buildkite/pipelines/es_serverless/verify_es_serverless_image.yml
index 7538da0cfbd40..c8899ed03731e 100644
--- a/.buildkite/pipelines/es_serverless/verify_es_serverless_image.yml
+++ b/.buildkite/pipelines/es_serverless/verify_es_serverless_image.yml
@@ -89,7 +89,7 @@ steps:
           queue: n2-4-spot
         depends_on: build
         timeout_in_minutes: 60
-        parallelism: 4
+        parallelism: 8
         retry:
           automatic:
             - exit_status: '*'
diff --git a/.buildkite/pipelines/on_merge.yml b/.buildkite/pipelines/on_merge.yml
index 815e4d9adb5e2..b03dc1cd9d913 100644
--- a/.buildkite/pipelines/on_merge.yml
+++ b/.buildkite/pipelines/on_merge.yml
@@ -109,7 +109,7 @@ steps:
       queue: n2-4-spot
     depends_on: build
     timeout_in_minutes: 60
-    parallelism: 4
+    parallelism: 8
     retry:
       automatic:
         - exit_status: '*'
diff --git a/.buildkite/pipelines/pull_request/base.yml b/.buildkite/pipelines/pull_request/base.yml
index c1cd68c6b04ab..c93e2c0a6daf0 100644
--- a/.buildkite/pipelines/pull_request/base.yml
+++ b/.buildkite/pipelines/pull_request/base.yml
@@ -87,7 +87,7 @@ steps:
       queue: n2-4-spot
     depends_on: build
     timeout_in_minutes: 60
-    parallelism: 4
+    parallelism: 8
     retry:
       automatic:
         - exit_status: '*'
diff --git a/x-pack/test/security_solution_cypress/cypress/e2e/investigations/alerts/alerts_charts.cy.ts b/x-pack/test/security_solution_cypress/cypress/e2e/investigations/alerts/alerts_charts.cy.ts
index 86dd58889a0a8..91e68ac4d5c8b 100644
--- a/x-pack/test/security_solution_cypress/cypress/e2e/investigations/alerts/alerts_charts.cy.ts
+++ b/x-pack/test/security_solution_cypress/cypress/e2e/investigations/alerts/alerts_charts.cy.ts
@@ -25,51 +25,46 @@ import {
 } from '../../../screens/search_bar';
 import { TOASTER } from '../../../screens/alerts_detection_rules';
 
-// TODO: https://github.com/elastic/kibana/issues/161539
-describe(
-  'Histogram legend hover actions',
-  { tags: ['@ess', '@serverless', '@brokenInServerless'] },
-  () => {
-    const ruleConfigs = getNewRule();
+describe('Histogram legend hover actions', { tags: ['@ess', '@serverless'] }, () => {
+  const ruleConfigs = getNewRule();
 
-    before(() => {
-      cleanKibana();
-    });
+  before(() => {
+    cleanKibana();
+  });
 
-    beforeEach(() => {
-      login();
-      createRule(getNewRule({ rule_id: 'new custom rule' }));
-      visitWithTimeRange(ALERTS_URL);
-      selectAlertsHistogram();
-    });
+  beforeEach(() => {
+    login();
+    createRule(getNewRule({ rule_id: 'new custom rule' }));
+    visitWithTimeRange(ALERTS_URL);
+    selectAlertsHistogram();
+  });
 
-    it('Filter in/out should add a filter to KQL bar', function () {
-      const expectedNumberOfAlerts = 2;
-      clickAlertsHistogramLegend();
-      clickAlertsHistogramLegendFilterFor(ruleConfigs.name);
-      cy.get(GLOBAL_SEARCH_BAR_FILTER_ITEM).should(
-        'have.text',
-        `kibana.alert.rule.name: ${ruleConfigs.name}`
-      );
-      cy.get(ALERTS_COUNT).should('have.text', `${expectedNumberOfAlerts} alerts`);
+  it('Filter in/out should add a filter to KQL bar', function () {
+    const expectedNumberOfAlerts = 2;
+    clickAlertsHistogramLegend();
+    clickAlertsHistogramLegendFilterFor(ruleConfigs.name);
+    cy.get(GLOBAL_SEARCH_BAR_FILTER_ITEM).should(
+      'have.text',
+      `kibana.alert.rule.name: ${ruleConfigs.name}`
+    );
+    cy.get(ALERTS_COUNT).should('have.text', `${expectedNumberOfAlerts} alerts`);
 
-      clickAlertsHistogramLegend();
-      clickAlertsHistogramLegendFilterOut(ruleConfigs.name);
-      cy.get(GLOBAL_SEARCH_BAR_FILTER_ITEM).should(
-        'have.text',
-        `NOT kibana.alert.rule.name: ${ruleConfigs.name}`
-      );
-      cy.get(ALERTS_COUNT).should('not.exist');
+    clickAlertsHistogramLegend();
+    clickAlertsHistogramLegendFilterOut(ruleConfigs.name);
+    cy.get(GLOBAL_SEARCH_BAR_FILTER_ITEM).should(
+      'have.text',
+      `NOT kibana.alert.rule.name: ${ruleConfigs.name}`
+    );
+    cy.get(ALERTS_COUNT).should('not.exist');
 
-      cy.get(GLOBAL_SEARCH_BAR_FILTER_ITEM_DELETE).click();
-      cy.get(GLOBAL_SEARCH_BAR_FILTER_ITEM).should('not.exist');
-    });
+    cy.get(GLOBAL_SEARCH_BAR_FILTER_ITEM_DELETE).click();
+    cy.get(GLOBAL_SEARCH_BAR_FILTER_ITEM).should('not.exist');
+  });
 
-    it('Add To Timeline', function () {
-      clickAlertsHistogramLegend();
-      clickAlertsHistogramLegendAddToTimeline(ruleConfigs.name);
+  it('Add To Timeline', function () {
+    clickAlertsHistogramLegend();
+    clickAlertsHistogramLegendAddToTimeline(ruleConfigs.name);
 
-      cy.get(TOASTER).should('have.text', `Added ${ruleConfigs.name} to timeline`);
-    });
-  }
-);
+    cy.get(TOASTER).should('have.text', `Added ${ruleConfigs.name} to timeline`);
+  });
+});
diff --git a/x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/bulk_add_to_timeline.cy.ts b/x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/bulk_add_to_timeline.cy.ts
index a27be939c1a8e..348b3a930a92b 100644
--- a/x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/bulk_add_to_timeline.cy.ts
+++ b/x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/bulk_add_to_timeline.cy.ts
@@ -34,7 +34,7 @@ describe('Bulk Investigate in Timeline', { tags: ['@ess', '@serverless'] }, () =
     cy.task('esArchiverUnload', 'bulk_process');
   });
 
-  context('Alerts', { tags: ['@brokenInServerless'] }, () => {
+  context('Alerts', () => {
     before(() => {
       createRule(getNewRule());
     });
diff --git a/x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/creation.cy.ts b/x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/creation.cy.ts
index 54fc0978e6120..b7236d7ea0d80 100644
--- a/x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/creation.cy.ts
+++ b/x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/creation.cy.ts
@@ -55,20 +55,16 @@ describe('Create a timeline from a template', { tags: ['@ess', '@serverless'] },
     visit(TIMELINE_TEMPLATES_URL);
   });
 
-  it(
-    'Should have the same query and open the timeline modal',
-    { tags: '@brokenInServerless' },
-    () => {
-      selectCustomTemplates();
-      expandEventAction();
-      clickingOnCreateTimelineFormTemplateBtn();
-
-      cy.get(TIMELINE_FLYOUT_WRAPPER).should('have.css', 'visibility', 'visible');
-      cy.get(TIMELINE_DESCRIPTION).should('have.text', getTimeline().description);
-      cy.get(TIMELINE_QUERY).should('have.text', getTimeline().query);
-      closeTimeline();
-    }
-  );
+  it('Should have the same query and open the timeline modal', () => {
+    selectCustomTemplates();
+    expandEventAction();
+    clickingOnCreateTimelineFormTemplateBtn();
+
+    cy.get(TIMELINE_FLYOUT_WRAPPER).should('have.css', 'visibility', 'visible');
+    cy.get(TIMELINE_DESCRIPTION).should('have.text', getTimeline().description);
+    cy.get(TIMELINE_QUERY).should('have.text', getTimeline().query);
+    closeTimeline();
+  });
 });
 
 describe('Timelines', (): void => {
@@ -112,7 +108,7 @@ describe('Timelines', (): void => {
 
   describe(
     'Creates a timeline by clicking untitled timeline from bottom bar',
-    { tags: ['@ess', '@brokenInServerless'] },
+    { tags: ['@ess', '@serverless'] },
     () => {
       beforeEach(() => {
         login();
diff --git a/x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/pagination.cy.ts b/x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/pagination.cy.ts
index 0037ae179c633..482bf04c048bc 100644
--- a/x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/pagination.cy.ts
+++ b/x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/pagination.cy.ts
@@ -46,15 +46,15 @@ describe('Pagination', { tags: ['@ess', '@serverless'] }, () => {
     cy.get(TIMELINE_EVENT).should('have.length', defaultPageSize);
   });
 
-  it(`should select ${defaultPageSize} items per page by default`, () => {
-    cy.get(TIMELINE_EVENTS_COUNT_PER_PAGE).should('contain.text', defaultPageSize);
-  });
-
-  it('should be able to go to next / previous page', { tags: '@brokenInServerless' }, () => {
+  it('should be able to go to next / previous page', () => {
     cy.get(`${TIMELINE_FLYOUT} ${TIMELINE_EVENTS_COUNT_NEXT_PAGE}`).first().click();
     cy.get(`${TIMELINE_FLYOUT} ${TIMELINE_EVENTS_COUNT_PREV_PAGE}`).first().click();
   });
 
+  it(`should select ${defaultPageSize} items per page by default`, () => {
+    cy.get(TIMELINE_EVENTS_COUNT_PER_PAGE).should('contain.text', defaultPageSize);
+  });
+
   it('should be able to change items count per page with the dropdown', () => {
     const itemsPerPage = 100;
     cy.get(TIMELINE_EVENTS_COUNT_PER_PAGE_BTN).first().click({ force: true });
diff --git a/x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/unsaved_timeline.cy.ts b/x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/unsaved_timeline.cy.ts
index 6c5e91ba748dc..9f368ca7b1220 100644
--- a/x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/unsaved_timeline.cy.ts
+++ b/x-pack/test/security_solution_cypress/cypress/e2e/investigations/timelines/unsaved_timeline.cy.ts
@@ -34,6 +34,8 @@ import {
 } from '../../../tasks/timeline';
 import { hostsUrl, MANAGE_URL } from '../../../urls/navigation';
 
+// https://github.com/elastic/kibana/issues/169021
+
 describe('Save Timeline Prompts', { tags: ['@ess', '@serverless', '@brokenInServerless'] }, () => {
   before(() => {
     cleanKibana();