There are too many (bad) websites that have my number for 2FA, plus my lifelong network of contacts all have that number.

Consider porting the number to something like Google voice or jmp.chat and get a random number you don't care about for your SIM.

It seems that Google Voice numbers can't be used for some 2FA services.

That's possible, but those services most likely offer another form of 2FA. Getting away from using SMS 2FA everywhere you can is best.

I know, but it's not always under my control.