For a long time, the main VPN that was recommended was Mullvad. iVPN, Proton and AirVPN were distant alternative recommendations. However, since Mullvad, iVPN, and some others removed port forwarding (for a good reason, you can read their blog post about it, but basically, human scum were using PF to allow others to connect with them while sharing child-based illegal material) many people had to make a choice revolving around PF.
PF allows you and others to keep a healthy "swarm," so it is a vital feature, particularly if you're hoping to download files that aren't recent & are no longer seeded by the original uploader. If the original seeder is gone, and everyone in the remaining swarm doesn't have PF, you're most likely not getting that file. Many people stayed with Mullvad, and some people switched to AirVPN or Proton, so that they could keep utilizing PF. If you're only going to download recent releases, I'd suggest Mullvad. Otherwise, AirVPN or Proton should be fine. I have no experience with either one, other than using Proton's free email service (I'm also testing Tutanota and Skiff, & liking Skiff the best out of all 3 so far).
I would also suggest doing a search for "ProtonMail court order leads to the arrest of French climate activist" and see if that bothers you. Example: see Mullvad's blog about "migration to RAM-only VPN infrastructure." Meaning, all the internet traffic going through their VPN service is kept on RAM, so when they say they don't have any logs, they don't and can't. Will Proton rat you out if they get a court order about you? I doubt it, but who am I to say. Although, email and VPN are not the same, but they are somewhat similar in regards to protecting your privacy. I believe AirVPN is also a trustworthy "no log" policy VPN with PF. Just do your own research and make an informed decision.
Me? I switched to Usenet instead of torrenting for anything other than recent releases. The good thing is that you don't need a VPN for Usenet (as long as you have the SSL connection enabled on SABnzbd in the server section, which should be enabled by default after installation). The bad thing is, it takes a little more research to understand how to best setup Usenet, but you're pretty much guaranteed to obtain your files, even years old. I don't need to keep Mullvad, but I have kept it for now, because it's pretty inexpensive and it's a great service, even without PF.
Short version: use qBittorrent, manually start it each time after you're VPN is active (do not have it start up with Windows or whatever you're using), make sure to BIND your VPN to qBittorrent (do not rely on just a kill-switch, notoriously unreliable), and using Proton should be fine.
EDIT: You may want to also research "nordvpn data breach" and "kape technologies malware" (Kape owns Private Internet Access) if one of those becomes an option for you. I'm not saying don't use either of them, but you should be aware of those things and make your own decision. I switched from PIA to Mullvad when Kape bought PIA.
EDIT2: Just in case people don't know, I believe Mullvad is still the provider for the "Mozilla VPN," just rebranded. And they have their own Mullvad browser (from Firefox), but I haven't tried it.