"people under 16", you mean children right?
"who also have the rights to freedom of expression and privacy", plenty of outlets for people to be expressive in the UK (more so than in the US for example, where the right wing will obviously attack any social media restrictions) that don't involve being fed junk divisive content from mainly US tech companies.
Privacy != anonymity.
Feel free to route your traffic via Wireguard. As long as it is not setup as a service for the mass evasion of age gates by children.
Nice try ! But the fact that the solution to protecting children comes with the maximum boost of government powers in the online world (across the set of all possible ways to protect children) is not a coincidence.