The UK is just saying the quiet part out loud. If you look at the EARN IT Act in the US or the "Chat Control" proposals in the EU, then the trajectory is identical. The UK is providing the "democratic" precedent that the rest of the Five Eyes will use as leverage. If you think the US isn't eyeing the Online Safety Act as a convenient trial run for overt or covert domestic policy, I’ve got a bridge to sell you.

EDIT: You added a lot more after I replied to your post.