Your local pub will have CCTV and some have names and photos of banned patrons behind the bar. Some bars and clubs have digital ID scanners upon entry.
Most online service providers who verify age are using third-party suppliers who don't provide any details of one's identity, just whether the user has been age verified or not. And much of that is done by recording a selfie, not handing over identity documents.
This is unfortunately quite a common tactic being used by people opposed to the OSA. Recently there was an article in the i newspaper which claimed you have to show ID to order pizza online, and it's because of the OSA. Turns out their source was a misleading tweet by a political activist who had ordered from Deliveroo or similar and were seeing the usual message shown to people who order alcohol. Nothing to do with the OSA at all.
I see much of the rest of it as being similar to alcohol licensing laws. Pubs and bars have restrictions on how they operate, for the good of the community and society.
This sounds like a misinterpretation. The OSA is primarily about making online service providers responsible for age verification, if they supply adult content. No different in principle from having to prove one's age to buy cigarettes, alcohol, knives, etc.
No-one says "cigarettes are censored!", because, obviously, they're not. Same for adult content online. It can still be accessed, as long as proof of age is provided.
Most online service providers who verify age are using third-party suppliers who don't provide any details of one's identity, just whether the user has been age verified or not. And much of that is done by recording a selfie, not handing over identity documents.