Nextcloud was too slow and bloated for me. I used Seafile for years and it was fine, but at some point I went to some more simple setup : sftpgo to share folders (sftp, dav) and syncthing for the folders I want to sync between devices. You can also set ignore lists in syncthing to ignore large dirs. Keep it simple stupid 😅

No offense, but I suggest you talk to a psychologist about this 🙂 I and many other friends did over here, and it really helps to unlock your full potential (everyone has different problems).