I am not sure you are understanding. I have dozens of boards, and if I grab a sample sketch that establishes an AP, it is automatically, according to the rules of the internet, set to 192.168.4.1 I have never looked to hard but that address is hard coded somewhere in the library code.
What I want to know is how to change that address without modifying library code.
Before I was given the eero routers I had no problem.
Is not the WiFi.softAPConfig the correct class member to modify the captive portal?