Yes, I re-wrote this website again...
For some reason Remix felt slower to me than it should. I also had it happen, that the remix production server crashed from time to time. But I am not sure if that's actually Remix's fault or if there is something wrong with the hosting platform I use.
Anyway - I decided to ditch Remix and went with good, old Next.js. Loading times are up to acceptable levels again and time will tell if it runs more stable.
Update
Since the re-rewrite this website is up 100% - So I guess I will stay with next.js for the forseeable future. I really should start sticking with what works best and not jump on every new framework/architecture. 😄