Using two different drives with Time Machine
You can have Time Machine backup to several drives, it will rotate among all configured and mounted drives. Two caveats

if you disconnect a backup drive, Time Machine will alert you the next time it‘s up for backup
If you disconnect a backup drive for a week it‘s next backup most likely requires a full scan of the source drive

It might be better to keep the two drives connected all the time and do alternating disk image backups to two other drives (and store those offsite).