back up to external hard drive

Do you have Time Machine set to manual or automatic backup? If manual, then you have to initiate the backup manually. Also check to confirm that you have an icon on the desktop for your passport external hard drive. If it's not there then you may have a connection problem with the external drive.

I use a WD my passport as my TM drive without issue. even on the latest release of monterey. but in my application, a once-a -week backup is satisfactory, so I cannot comment as to if using auto backups would cause an issue. but I would think not.

I'm sorry that you've had that issue. but you did ask if anyone had the same issue. (also with WD my passport) and in my case, I did not. I would have thought it was a drive failure. but since you had two drives fail at the same time, a drive failure is highly unlikely. so rather than disposing the drives, I would try and erase and reformat them to see if you can repurpose them as external storage.

I use a WD 4tb USB drive to backup to without problems and are running the latest version of Monterey.

I agree with Jeffrey that multiple drive failures is unlikely and if possible try the drives on a different computer and try a different cable to be sure it's not the problem. If you format the drive as exFAT then it will be readable on both a Mac and Windows machine. Also, know that when you use Time Machine, it will automatically reformat the drive and it will be unusable for other work.