Nextcloud for me too, would break because of updates requiring manual DB updates sometimes, apps would randomly stop working after updating too, or the 2 times it caused total data loss on all my synced devices and the server itself which required a full restore from backups.
After getting rid of it and switching to Syncthing + Filebrowser + SFTPGo for WebDAV I haven't really had anything break since then (about a year now). Stuff also runs much faster, NC was extremely slow even on good hardware with all their recommended settings for performance.
If Nextcloud "caused total data loss on all my synced devices and the server itself" I would probably do something unsavory to any responsible party I could locate, and take 10 TB of data out of their lousy hide.
Yeah the first time was the time/date bug they had (still have?) where it set the time on every folder and file to 00/00/0000 00:00 across all clients and the server.
Second time was I disabled virtual file support on my laptop so it would sync everything, but instead it went and wiped all the files from the server, because for some reason their sync client assumed the laptop that now had no files on it should be the master source or something.
Their own docs even state that's how you're supposed to disable VFS, with no mention that it will wipe your server clean.