They have tons of servers worldwide for varying use cases, the speed is great, and I’ve never had to contact support.

Tldr, probably not. Proton has an article saying no, but that article is older than their new Stealth protocol which was built to work better in anti-vpn environments.

I would also read this article which has some information you may find useful.

Available information indicates that it’s all processed and stored on-device (and even encrypted). I’ll wait for confirmation from security researchers, but the available information I’ve come across says that it’s all done locally.