Hi,
The MikroTik hAP ac lite (RB952Ui-5ac2nD) would be a cost-effective and lightweight device that is capable of connecting to a hotel WiFi over both 2.4GHz and 5GHz frequencies, and can be configured as a WAN, firewall it from the LAN, and allow your LAN devices over WiFi through your own SSID. There isn’t a default setup for this particular configuration, but it can be set up through MikroTik’s RouterOS software.
Power via USB … check the Mikrotik MQS. Works fine with power bank+ hAP ac Lite. I can even add mAP Lite at the PoE out port of the hAP ac Lite, all powered at the same time. Or just powerbank+mAP Lite for the lightweight travel set. (Config of the mAP Lite is a bit complex, if no ethernet or MQS available to set up on the go. See “Travel router”)