Move thumbnails, cache to a different drive

New here, I got HA OS running in a VM managed by proxmox, the OS is installed in a ssd but Im afraid that cameras thumbnails (and other cache) makes too many unnecessary writes to the ssd. I got a secondary HDD on the same system that I use for backups. I already set this drive on the VM, but I cannot see it on HA. How can I enable this drive to use as a custom path for camera thumbnails, backups, etc ? I don’t want to move the entire OS there