I exclusively use it via VPN, with a ProtonMail address from the web (so many login notifications) while like, commenting, and subscribing on politically controversial content and soccer.

Three, almost four months in and zilch. It’ll be a good test case anyways.

They flagged my phone number-less account after four months, probably because I replied to a high traffic thread.

I think the key to using a phone number less account is to use it as much as you can in read only mode.

Fixed wireless ISP in the US and I hit a captcha on every site from time to time when logging in (and sometimes just trying to read-only) - and I'm effectively blocked from anonymous sites.

I can "lock in" an apparent IP address, i.e. ssh to some box with no-ops; but that's either per-connection or still NAT enough that I get flagged. att aggregates all such connections at F5 routers in large cities, mine is in Dallas, for both of my fixed wireless connections.