Regarding e-mail: "riseup.net" requires that a long-time user vouch for a new user and invite them. If the new user quickly turns into a complaint magnet (there's a coming-of-age period after which their actions are considered their own), both the user and the inviter will be held responsible (kicked off the service). I think (hope) they aren't so strict with VPN, but they have limited people and could not administer a mess made by a big bunch of people.

Needless to say, none of my (anarchist) comrades have ever been kicked off RiseUp, but they don't send spam or threats, they just send their cat pictures encrypted with GPG, causing the authorities endless work. :)

Just like every reasonable service, RiseUp has a few technical mechanisms to ensure they aren't compromised (disk and inbox encryption, etc) but obviously those can't help against a dedicated and well-resourced adversary.

So, whatever e-mail server you use - use PGP / GPG. :) Then the adversary must compromise your device. If you are hardcore, encrypt and sign on an offline device. Then the adversary must breach the air gap.

(I used to sign releases for some anonymity-related project years ago. Those were the times when I seriously took measures because others depended on me. Currently, not so much.)

P.S. As for the lack of resources at RiseUp: this can be alleviated by donating to them. Which reminds me, I should set up a small regular donation to their representative organization in the EU.