Any VPN services you would recommend above the rest?
I recommend having at least one backup VPN. Proton, Mullvad, and IPVPN each have strengths and weaknesses for specific usecases, but are all good choices.
Would you run two or more at the same time?
What are the individual strengths of each, and what you of work is each best for?
Mullvad servers tend to get blocked by more sites than Proton so I don't recommend it for installing as an always-on VPN on a firewall for example while Proton is a good choice. It's easier to set up Proton on QubesOS ATM. Mullvad doesn't require any sign-up info like email etc. IVPN has multi-hop VPN routes so it's more private, but will be slower. These are just a few examples.