Age verification doesn't need photo ID online. A small 1c credit card transaction is enough. They could force this to be via Apple/Google Pay so kids can't just steal their parents card details. This way no bank details are exchanged either.And that is just the beginning. I fully expect all social media to require photo id in the near future.
Social Media requiring this sort of age verification would kill bots and spam in a day. If anything they could go back to the old '$1 per year' WhatsApp charge. A network as small as Bluesky would get $32m in revenue on an annual basis, more than enough to maintain the company and pay the staff.