Sometimes the singular “they” is easy to understand and makes sense. I think Remarkl is correct that this is usually when we don’t know the gender of who is being referred to. Jane Austen uses it very frequently, largely because she was mostly writing about women, so the traditional form of her time, (using masculine pronouns for the unknown) would sound weird.

At other times the singular “they” is confusing, and sounds like woke virtue-signaling. if it were up to me, I would use “she” whenever “they “ was confusing or clumsy. But it’s not up to me, so I’ll go along with the crowd and accept the new usage. It does result in some clumsy sentences, but there are worse things to worry about.