I tried out a few and they seem to mess up Mac Mail, even when I apply split tunnelling with those that offer it. Split tunnelling basically allows you to exclude an app from going through VPN. After a several days my mail drops out of service and I have to create new passwords and reset two accounts on 5 devices. ExpressVPN has split tunnelling fearer but still causes grief.
I have done a lot of reading and it appears it messes with protocols and I think the keychain. I don't need it at home but I'd like it for travelling and insecure networks using my laptop.
NordVPN caused the same issues. I removed it and a week later (yesterday) my laptop would lose the internet connection after about 5 minutes. I checked the network connections and Nord was there flipping back and forth between the Ethernet connection. Sneaky.
Any experience with VPN? Any suggestions?