How should we display timestamps ?

[Dehelssey]

I stumbled upon yet another post of someone complaining about relative timestamps (like "2h ago") and asking for absolute ones (like "20:50")

but that raises other questions :

do we display the same date format for each post
like day / month / year / hour / min

or just the hour for today's posts and the day for previous ones ?

what type of date formatting ? January, 19th 2022 ? 19 Jan 2022 ? 19/01/22 ?
12h mode or 24h ?
How can we let user control that ?

Like i said, so many questions.

SO let's start with the first one :