Time Maschine Backup
How to back two MacBook pro’s up to one SSD
MacBook Pro 15″, macOS 14.7
Back up your Mac with Time Machine
Advanced users: If you add an APFS volume to the external storage device, you can use one volume for Time Machine backups and the other for storage of other files.
Caveat - If the 1 SSD Drive, with a second APFS volume fail ?
What then ?