The UK's awful Online Safety Act does not require Apple to implement device-level or Apple Account age verification for iOS features and App Store access. The Act primarily targets user-generated content platforms and websites, not operating systems or app stores, which is why Ofcom is praising Apple's voluntary move.
Lots of moaning at Apple here. Your beef is with the UK government. Obviously Apple will comply with all legislation in order to be able to sell their products. This is actually pretty trivial compared to the loss of ADP in the UK.