I've been using Proton VPN for just over 2 years now and I really enjoy using it. It's one of those tools I just keep on and kind of forget it's there. I do a lot of torrenting of files, and the speeds I get have been fantastic. I've never really experienced any slow downs.
Proton VPN has thousands of servers on the paid plan so the servers will rarely become overloaded.
My only complaint about Proton VPN is the Linux app. Comparing it to the Windows and MacOS version, it feels neglected and in desperate need of a UI update.