Well that's strange, because I just updated to 10.3.1 hoping this new version would fix it but sadly it didn't. I still have the same issues and my only solution is to revert back to Drupal 10.2.7.
I even tried it with a completely fresh Drupal installation to see if it was one of my other installed plugins that was causing the problem.
> So I installed a previous Drupal version like 10.2.2 (I also tried with 10.2.7)
> Installed some modules like Paragraphs, Layout Paragraphs and I even installed the Gin Theme
> Set up 2 paragraphs and added a Paragraph field (that I simply names field_content) to the basic page content type and set its display to Layout Paragraph Builder (Experimental). Everything works perfectly fine :
> Than I updated Drupal to 10.3.1 and it stops working (logs don't show any error) :
But I also figured out that some other generic pages like the admin/modules/uninstall or admin/reports/updates don't work anymore.
It seems like the moment I install a module or a theme via compuser everything goes wrong in Drupal 10.3 or 10.3.1.