Reading https://overengineer.dev/blog/2019/04/08/very-precarious-narrative.html explains vulnerabilities to VPNs. I was aware of several of them, but some I wasn’t.
Are VPNs still useful for torrenting?
Depends, largely on how motivated people are to identify you.
If you infrequently torrent a few games and movies, using a VPN will probably be enough to deter most of the law firms specializing in churning out copyright notices. They go for the low hanging fruit first, aka the users without a VPN.
If you on the other hand were to engage in torrenting highly illegal stuff, and were therefore to become a target of state law enforcement, you’d be in a whole different kind of trouble. A VPN would likely not be sufficient.
If you are tech savvy and the stuff you want to torrent is somewhat mainstream, I would recommend torrenting over i2p. You should be able to find all the info you need to get started on their website: https://geti2p.net/
i2p is an anonymity network similar to tor, but the implementation allows for torrenting much better than tor. It is worth noting that i2p is not a drop-in replacement for a vpn and you will only be able to access content on the i2p network, however you can easily request that things be added and there will usually be a seeder in a day or two.
Comparison to Tor for those curious https://geti2p.net/en/comparison/tor