That depends on a number of things, like do you want to seed (if so, Mullvad is out), how much do you plan on downloading (if a lot, a VPS may be out), if your ISP blocks any of them, etc.

I generally recommend Mullvad or DIY w/ a VPS (I DIY a wireguard VPN on a VPS), but just try some out and see what works best for you.