Do you use restic to move the backups to remote on it’s own? Or are you using rclone to move your restic repo to remote?

This is what I attempted by using *.mytailnet.ts.net, but that did not work. How would I enter this in my export file?

Phoniest

Beyond 3 devices, Tailscale costs money

I think you mean beyond 3 users. You are allowed up to 100 devices in the free tier.