“Legitimate interest” is used to cover a wide range of bullshit. I’ve seen it in a shop that had facial recognition cameras, they had a little sign by the tills that said “We use facial recognition for crime prevention and legitimate interest purposes” without even a clear way of opting out.

If they do it like Instagram, you have no control over the categories that get added and you can only opt out of one at a time, meaning the process will be extremely tedious and has to be regularly done.