For the second time I have the problem, that my newest savegame (and the newest Autosave) don't load andymore. When I want to load, I got stuck at the loadingscreen. First I got the issue three oder four playing-hours before, but after it, everything was normal untill now...

Does anyone knows the problem and maybe even the solution?

Here is the best solution about how to play Fo:NV without issues:
https://vivanewvegas.moddinglinked.com/intro.html

Mods that are unofficial patches. You can but don't need to run additional (game changing) mods.

If you want "vanilla game" then accept bugs and errors like those above with savegame load, crashes etc.

I played vanilla version (for the very first time, long time ago), later with some unofficial patches/mods but after"Viva New Vegas" I will not use other solutions. This one is the best.