How'd you do it with a vpn? Doesn't it still need your facebook account to be from the US?

Nope, I just went to muse.ai and typed an email. It created a new Meta account with it and once you interact with Muse once you no longer need the VPN because the service itself gets added to your Meta account.

I then linked my Facebook, IG and others to this new Meta account so that Muse can access them.

No problems whatsoever