I have happily used PIA for years on Ubuntu and macOS and Android, but I never, ever use their clients. Just download the ovpn files[1] and set them up with the native support built into your OS (or use something like Viscosity for more functionality). On an unrelated note, I'm happy to know that my (reasonable) annual subscription allows them to support FOSS projects, they should really publicize that more!

1: https://www.privateinternetaccess.com/openvpn/openvpn.zip 2: https://www.sparklabs.com/viscosity/