This isn't necessarily true. If you are using an identity provider, you can still perform a password reset on GitLab and set a password there, bypassing your 2FA on GitHub. You usually shouldnt rely on IdP 2FA unless the destination system enforces IdP signin every time. There is a group setting in GitLab that does that, but it will only apply for that group.
I have a Rivian and it works great with no subscription. The only thing you can add via Sub is a hotspot, which seems reasonable to me.