What is the best external SSD for a 2021 iMac?

Sandisk Extreme SSDs had problems with losing data a while ago. I don't know if they have been fixed yet, but I've steered clear of all Sandisks for a while and stopped using the one I've got (which is OK, so far) as a backup or archive.

Most disks will do just fine. i use and like LaCie drives. The key thing is to not use any of the so-called maintenance apps that often come with drives. Reformat, if needed, only using Disk Utility.