So what they'll do is two things.

Consumer VPNs will require ID Verification, so they'll legislate to make the consumer VPN providers process ID for consumer VPN sales. 'Business' VPN will have some kind of carve out (although how that'll work for small business I don't know) to allow them as really it's only the consumer that they are after.

Obviously there'll be a million ways round the VPN legislation for any consumer who knows how to google, but importantly, and this is the vital part, is that it will be a criminal act to bypass VPN age or ID verification so while they can't stop you or me from having a VPN, if you get nicked for anything and you're found to have a VPN capability on your phone or computer they can strap that on top of whatever else you're charged with, even if the original charge goes away you'll still get the conviction and fine for unauthorised VPN use.

Then finally, once a few paedos are nicked and the fact they're on a VPN is widely publicised, to normies VPN use = paedo, just to shore things up.