The technology bit doesn't really matter though.
The real problem is that the legislation would bring the power to prosecute people who use them or use it against them.
The security services aren't having any of that shit because it puts their position at risk both from the front-facing side and recommendations and guidance issued and from their own operations.
The power to prosecute and the actual ability to prosecute are two different things. They currently can't prosecute CSAM offences nor piracy due to capacity. It won't happen.