Best VPN to use on Ubuntu

I had a system running Lidarr, Radarr, Sonarr in the past with no issues. However it has not running for the last several months. I set up a new one this weekend. I had it downloading quite a few files. When I got home today it had downloaded about a third of them. However, I also found an email from my ISP that read in part

We have received a notification by a copyright owner, or its authorized agent, reporting an alleged infringement of one or more copyrighted works made on or over your ISP name removed Internet service."

The email also said repeated violations can result in my service being suspended or terminated.

Does any one have a recommendation for a VPN recommendations and/or recommendations on how to prevent this in the future?

I didn’t even have it downloading for 24 hours. How did they know?

Thank You

I have both Sonarr and radarr and I use ProtonVPN. It’s been great to avoid those notifications the occasional time I have to manually look for something. The big thing you want to make sure of is whichever VPN you chose that they protect ALL data coming and going from your device, and that they don’t collect any information. Way too many will not protect torrent clients and collect data.