Now I see. I'm not surprised. Proton's free tier has been used by scammers since inception, so the free tier has its limits. I think most of the people who have been saying this has never happened to them are actually paying for Proton services.

Again, if you want, you can even pay in cash through the mail, they will generate a random email address for you if you don't want to give them one (I can help you with this process).

You do not have to give them a backup email—in fact, they highly encourage you not to because that's personally identifying information.

You can sign up over Tor. I highly recommend actually paying them for their services. It seems like you have been enjoying their services enough for that to make sense.