In that case I would pickup a cheap USB Ethernet dongle (or 2 if the laptop doesn’t have an onboard one)
Wall > Ethernet 1 and router > Ethernet 2
Configure windows to share Ethernet 1 connection to Ethernet 2 (Builtin functionality since Windows 7 iirc)
Configure the router for minimal power to the radios, use your laptop to handle captive portal and there should be no DHCP interference concerns with the Windows laptop on the middle in this fashion
Boom done, congratulate yourself a lil for a small win over corporate greed lol