How can a event/variable trigger the webserver to switch to an alternative webpage on an ESP32 AP Webserver

[12345PJ]

Hi

I am fairly new to Arduino and ESP32.
I want to have an AP running with an async Webserver, using Arduino, no problem, I found examples which are clear.

Next, I would like to have the webserver to switch to an alternative page whenever a variable is set, e.g the ADC value is above a certain value or an input pin is toggled, if anyone has an example, that would be great (or any other help to achieve this).

The main and the alternative page will have data on it which must update automatically every 1-5 second, not the same data on the pages, this I believe I can manage myself.

I also wish to have a landing page so whenever the Android tablet connects to the AP, it will be automatically redirected to the main webpage (index.htm) but I am not sure this can be done, it is an old tablet without BLE, otherwise it could be solved with a BLE beacon i believe.

I am doing a project and replacing my Display in a Peugeot 407 which is not visible unless it is cold.
The CAN messages I hope I will manage to receive and decode and if a fault appears on the car, the display must show an alternative webpage with the fault and the explanation.

Code a.s.o when (if) I succeed, will be publicly available, this is for fun, not for making money.

Any help is highly appreciated, Br Peter