I use OPNSense and OpenWRT myself and there's no way you can make travel routers this convenient with them.
Not as convenient as this travel router sounds though, but comes close-ish for techies. (wish it didn't require that tweak via SSH. Maybe it'll be added)
I wish Eero offered this feature. I bring three eeros to Airbnb’s to replace their crappy WiFi with my same SID, but it would be nice if it connected back through the home internet.
In my defense, I'd argue that the average Tailscale user would be comfortable running an SSH command! And GL.iNet is just one very minor tweak away to making this entirely possible from the GUI. (though they might be intentionally avoiding it because of the support burden of quirks caused by Tailscale acting as a subnet router...)
That will be fun for browser geolocation based on WiFi name.
So the usually ssid is in my home country, and another ssid is based somewhere else geographically.