Disk Utility can't erase or repair disk.

24" M1 Mac 2021

Sequoia 15.1.1

WD Passport

This external HD stopped unmounting several months ago. It contained a little over 1Tb of photographs. The only way to unmount the disk was to turn off the computer. It just kept giving me the message that it was in use by another program. I tried all methods (signing out and signing back in, etc.) but nothing worked except powering off the computer. Anyhow, this was getting to be a pain so I decided to try to repair the disk but kept getting the message that it couldn't complete because the volume couldn't be unmounted. I finally moved everything to a new external HD and then tried to erase the WD passport but got the message shown below. I then had my husband try it on his 19" MacBook pro running Sonoma 14.6.1 and it successfully erased the disk. I loaded some more pictures onto the disk and tried erasing the contents and reformatting on my Mac and all went as expected. Could this be a problem with Sequoia, disk utility, or the external HD? Do you think I can use the disk safely? By the way, the photos I moved to another disk are mounting and unmounting properly so there doesn't seem to be a problem with any of the files.