Have you tried using the gitea backup and restore command ?
https://docs.gitea.com/administration/backup-and-restore#using-docker-dump

In docker, you just have to copy the data from the docker volume to your new system and put it in the same docker volume

It works flawlessly everyday for me, I recreate the running full server on a spare one.

Have you tried using the gitea backup and restore command ? https://docs.gitea.com/administration/backup-and-restore#using-docker-dump

In docker, you just have to copy the data from the docker volume to your new system and put it in the same docker volume

It works flawlessly everyday for me, I recreate the running full server on a spare one.

Yes, I have tried before, but the first few attempts have all failed (without any error messages or normal access). Yesterday, I manually processed the files and permissions and finally managed to use them

I hope Gitea can backup and restore with just one click. Whether it's native app or docker

Even Gitlab does not propose this. There is too much risk of loss at stake.
https://docs.gitlab.com/ee/administration/backup_restore/restore_gitlab.html

Even if an automatized Gitea backup would be neat, the administrator have to make sure the server has space, it is not corrupted, and so on, at this point, this is not anymore a gitea topic.