I use syncthing to copy important files between pc, phone and proxmox server. Syncthing can be set up with version control so it keeps old versions of files.
Only the proxmox server is properly backed up though. to a proxmox backup server running in a VM on said proxmox server. the encryptred backup files are copied to backblaze using rclone
Not sure if this is what you are looking for, but it works for me.
TLDR syncthing for copies between local machines, and proxmox backup server and backblaze for proper backups