> encrypted Time Machine to a network location
this has a bonus feature where it will slowly corrupt itself over time and offer to start a completely new backup instead.
I backup to TrueNAS which configures Samba/ZFS to take a snapshot before each backup. If TM decides to corrupt a backup, I can revert to a snapshot. I've only ever had to do this once in years of operation with several Macs backing up (each to their own share).
Sometimes it's pretty quick.
to go forward, you must backup
That would happen around once a year when I used the 2013 AirPort Time Capsule.
It seemed to stop killing itself when I moved to a ZFS backed samba share.
Funnily enough I also kept snapshots enabled because I was expecting TM to bork itself eventually, so I could always rollback to a working state but I don’t remember needing to use that.