The OptimizePress Button in the tool row at the top of the page (when logged into WP) also doesn’t seem to be clickable for some reason, maybe thats connected somehow?

Well, that is our problem. The Gallery in the middle where there are only 8/9 Pictures shown with the last (middle) one supposed to be a picture with a Phone Number. I deleted the old picture, since I thought the gallery maybe had a problem with 2 things named the same. If I click on the Layout Editor and on the Masonry Gallery you can see there are 9/9 Pictures, but the one named “Kontakt” isn’t showing up on the site.

Edit: Just looked at the site / Layout Editor again, now there were only the 8/9 that show up and when I added the new Kontakt it got added to it normally. This was tried yesterday multiple times (working in the Editor), never affecting the actual site. Now it works, so thanks!

The pagesize is just a bit more narrow than before and the main issue is the fact that the sidebar on the right gets squished together.
For example: https://www.rejzek.at/behandlungen/brustvergroesserung-eigenfett-lipofilling/
For some reason the properties don’t change even though they are changed in the Enfold Menu.