Proton mail suspended my account for using to or over VPN a few years ago. Don't underestimate these third party services. I was a little shocked back then, but now I take it for granted that all third parties are security holes.
How can you know that? Asking because couple of our contributors in the 🇪🇺 region are already having severe issues using Tor. Wait times of 20+ mins, downloads from websites browsed on Tor taking just as long, or until one loses patience.
Our guess is at the Internet Provider level there are firewalls being set up for Onion sites.
Do you have evidence for otherwise?