How do you tell if a beta test is giving you useful results?

I’m curious about something with beta testing. If five people use the same app and only one person runs into a problem, how do you decide whether that problem needs fixing?

I feel like testers can have very different experiences depending on how they use a product, so one person saying “everything worked” doesn’t necessarily mean there aren’t issues.

For anyone who has tested apps before, how do you normally separate a personal preference from an actual problem the developer should know about?