MacBook Pro Time Machine fails with SMB disk over VPN

Hello, I am a road warrior and would like to backup my M4 MBP (running macOS 26 Tahoe) while traveling via my home VPN where I have a Mac mini (also running macOS 26) sharing a TimeMachine disk via samba protocol but I have not been able to run a backup, says cannot find disk..

I can connect/mount the shared disk manually in Finder (Go -> Connect to Server... and entering smb://10.0.0.2/TimeMachine) and I see the sparse disk image bundle but after doing so it still says cannot find disk; any ideas?