can I use a thumb drive to backup with time machine

Betsey Hansell wrote:

Can I backup my Mac hard drive to a thumb drive using Time Machine

Using a thumbdrive as a TM backup...(?) not recommended.

Not as stable/dependable/capacity limitations do not make is as desirable as a dedicated external drive.

Back up your Mac with Time Machine - Apple Support

Slow performance, poor reliability, and limited capacity makes this a bad idea.

I use and recommend external Crucial X8 SSDs that are fast, reliable, and compatible with my M2 Mac mini pro, my 16-in M1 MBP M1 Pro, and your Mac Studio — all running Ventura. You want a TM drive formatted as APFS and sized to 2 - 3 times the capacity of your internal drive that you are backing up.