ZeroTier with VPN-Provider

Hello,
i have a pretty specific question, how safe/secure is it to use ZeroTier with devices that are behind a VPN Network like MullvadVPN etc…
For example, a Phone that uses ZeroTier access a Server with ZeroTier, but the Server is behind a Router that is connected to a VPN Provider, so the Public IP is shared by numerous people that use the same VPN Profile of the provider.

As i understand it, ZeroTier uses UDP hole punching, but wont it open the UDP port for everyone with that shared IPv4 from the VPN Provider?

I wouldn’t expect this to work. “Privacy” VPNs like Mulvad aren’t going to allow incoming connections to be established. Only incoming packets related to outgoing requests.

I have tested it, and it does work.
Im just not sure if its safe/secure.

Well we cannot guarantee that it will continue to work.

As for security, everything in ZeroTIer is encrypted peer to peer. It’s no more or less secure with or without running over Mulvad.