Hello @dsp76
Good to read that you found a solution for you that works for now.
Regarding the issues with IONOS S3, we will have to look into it.
Just read the following topic Backup to Hetzner Object Storage failing regularly and now reading that you have no issues with Hetzner SSHFS.
It seems the experience between users are worlds apart.
Maybe some insights about:
amount of apps
what apps
tgz or rsync
backup size
schedule
full encryption
file name encryption
from you @dsp76, @p44 and @ccfu might reveal some common issues?