It kinda depends on what you're trying to do.

The VPN obscures your traffic by sharing a WAN IP with many other users & hiding your traffic from your ISP. Mulvad allows you to do this anonymously.

I believe tailscale creates a tunnel between 2 devices even when you don't have a static IP address.

I do something similar with a cloudflare tunnel connected to my nextCloud server via my domain.

I think tailscale is for when you don't want that connection to be publicly accessible. I haven't played with it but it's on my list.