Germany passed an anti-terror law a few years ago, getting a phone number requires the same level of verification as opening a bank account.

Even before that prepaid phones have been a strawman argument, actually maintaining a 2nd number in the long run is quite a bit of work since it usually expires if you don't use it enough.

And then you typically need to do some kind of identity verification to activate it.

In Austria, Belgium & Germany you do, in Croatia & The Netherlands you don’t

Possible that's typical, but it's certainly not universal

Not in the UK you cant.