You can but have to use their partner link. I bet you could do this with Headscale with your existing Mullvad account but never tried.
nostr:npub1m2jphmdkskgnvwl5gplksl9e0zwv2sldqf9mwlpz6tyymz84g9fsqr3wgu do you have experience with this?
Discussion
What’s head scale?
So it’s an open source tailscale… Not sure that fixes my issue.
Yeah not sure. Headscale requires more manual configuration so maybe not ideal but this issue might help: https://github.com/juanfont/headscale/issues/1545. I'd just recommend staying on Tailscale and either set up Mullvad through them or take the L on this one. Sorry I couldn't be more help.