Your example is unambiguously plural. It’s not a good illustration of “they” creating confusion.

It’s truly not a problem. I could contrive a reason to talk about a couple (they plural) and a nonbinary person (they singular) and end up with sentences where you don’t know which I’m referring to, but the exact same issue happens if I’m telling a story about two “he” or “she” subjects. And it’s solved in the same way.