[wip] re-setup optimizers and model after restore

[awaelchli]

What does this PR do?

Fixes #7535

Random, to check which tests don't pass.

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[codecov]

Codecov Report

Merging #7578 (7c26290) into master (f4f51e0) will increase coverage by 44%.
The diff coverage is 100%.

@@           Coverage Diff            @@
##           master   #7578     +/-   ##
========================================
+ Coverage      44%     88%    +44%     
========================================
  Files         197     197             
  Lines       12865   12879     +14     
========================================
+ Hits         5649   11305   +5656     
+ Misses       7216    1574   -5642