It worked!!! Thank you both so much! It is possible to see the type of a file. So I could simply delete some videos and /e/OS would boot normally again!
1|FP3:/mnt/userdata/media/0/wIQzCnKK9bp7ZKlZTZC9yB # ls -l
total 340124
drwxrwxr-x 2 media_rw media_rw 4096 2022-11-09 11:38 7ZeokuV,R3Ql3iEToWKOSC
-rw-rw-r-- 1 media_rw media_video 15933812 2020-12-20 17:01 B,wdUX7x,T60iwFvPWDIoQrxTkwgxQYhSilb,A
-rw-rw-r-- 1 media_rw media_video 23049127 2021-04-17 07:57 HHFLEXY4CcLwD,pjhK5HS1P,Gc9hFVakwpAXKA
I think /e/OS should ensure that it can always boot (if that’s possible), no matter how much memory is used. I think user applications should not be able to polute the system so much that /e/OS cannot be booted anymore. Maybe an issue can be opened for this?