What isn't free software..?

I think you should make it clear if you are talking about VPN services or client-side apps here. If they provide normal standard protocols like Wireguard and OpenVPN, they can be used without having to install any provider-specific apps.

Regardless of provider it's generally preferred to use third-party software to connect. VPN providers that don't even have their own apps don't qualify as good for you either?

Demanding the whole stack be FLOSS is a bit silly in this context. None of the ones you mentioned open-source most of their backend systems either AFAIK.

I think you should do your homework better before you speak so widely and absolutely dismissively with such claim of authority. It is not helpful.