By VPS, I mean a generic compute instance that can run whatever you want. Like a Linux instance. I'm not sure what you mean by "VPN providers offer VPS as a substitute" in that context.
Paying by card isn't enough to verify age. They'd have to specifically verify via passport or other ID.
I think they would include AWS and the pushback would be ineffective. Many AWS users could be immediately age-verified by existing payment card info.