I'm pretty new to the Proxmox/homelab world and learning all the time. My "server" is a repurposed Dell XPS 8940 with 5 drives. The boot drive is on a 256Gb ssd. My VM's and there backups are on a 2TB nvme. There is also a 3x2TB drive ZFS pool used as a smb share.
This project is just for fun and for learning and I keep nothing important on it and except for the smb share there are no important services running. But... I think I need a better backup strategy than what I'm currently using.
What I do now is boot to a Rescuezilla USB stick and save .img's to a USB docked 12TB Seagate Ironwolf that is connected to a 5GB USB-c port. It works for me. I've even done full restores to both the boot and nvme drives with zero issues. So I know that this is a workable solution. I wouldn't even dream of using the ZFS pool for backups as the drives are 2.5" WD Blue hdd. Not what I would consider reliable storage.
My budget is exactly $0 so paid software or adding another physical server is out.. I'd prefer something with a GUI as my skill level is in the barely novice range but I'm not afraid to use the CLI. What do other folks use?