Tether a burner with an esim over USB, or a "mifi" box with an ethernet cable; though the latter are harder to secure. Important to mind is to not run your own wifi endpoint (and defo not bluetooth!) if you can help it, because every phone around you scans and reports those back home. Yes, everyone has spyware in their pocket.

About 18 months ago I had this project to have a little dev board (rk3328, later switched to 3588) with a strong usb antenna and have it act as an ethernet->pubwifi router, but captive (the "login" screen) is hell and I haven't taken the time to develop something neat for that, because on AOSP it just works. So I guess that if you find yourself in a situation where you absolutely need to use public wifi, tether it through the burner too. I'm currently enforcing VPN on all end devices so I haven't tried it, but you can also tether through VPN on Android, I think.

VPN