I can't boot anymore


after solving some beginning issues, my Fedora 33 was running almost good. I couldn’t use openvpn and had some other small issues.
But today I wanted to restart the whole PC because I couldn’t open pictures with my standard program and also couldn’t change it. Then after finishing everything, I closed everything and made a normal restart, but it never booted again. First there was the Fedora loading screen forever and after some new tries I had an error that LightDM isn’t working. Nonetheless I couldn’t start anymore.
Is there a good way with a live version to repair it or shall I install a new distribution?
Thanks for tips

You can try to switch to another VT and downgrade LightDM, or try another DM.
If you cannot access the text console, try chroot from a live session.
Also check out the related logs to identify the cause of the issue:
Viewing logs in Fedora :: Fedora Docs