Connect Chromecast to a wifi with 2-step sign-in
A Chromecast doesn’t support signing in to a wifi that requires you to sign in through a browser. You can imagine most hotels are using this kind of wifis.
A wifi with 2-step sign-in is probably using a MAC address as an identifier. Therefore, a way to solve this is to spoof the MAC address of your Chromecast using your laptop, sign in to the wifi, un-spoof, then connect your Chromecast to the wifi.
I tried it, and it works for Emporium Suites By Chatrium in Bangkok.