What about an ESP8266 with UART adaptor like this ? You'd have to set it up in Arduino to become a pingable host though, if you know how to do it. And set your router to provide it a reserved fixed IP of course.

https://www.amazon.com/ESP-01S-ESP8266-Wireless-Adapter-4-5-5-5V/dp/B07KF119YB/ref=sr\_1\_6?dchild=1&keywords=esp8266+usb+uart&qid=1625740998&sr=8-6