If the UK citizens want Chat Control they should have it. If they don't, they should not elect a government that wants it. Same goes for almost every issue the EU is pushing. Not everyone in the EU needs Chat Control just because the UK citizens really want a government that will give them Chat Control.
Sure, when you frame the question as, "do you support these measures to ensure children don't have access to pornography?", of course people are going to support it.
Present evidence that the new laws will be a danger to their fundamental rights and maybe you won't get quite as much support.
Also, that survey shows that there's broad support even though the same people don't believe the new laws will be effective. So... that's pretty stupid.
No EU means that this law would have to passed in 27 different countries whihc would make it much harder to put this many people under surveillance.
So, in this particular case no EU would be a clear benefit because it would give us time to see the effect on this law on the neighboring countries first, just like we saw with the UK and the OSA.
I am becoming more anti-EU by the day and this is just one more nail in the coffin.