PPMEncoder VS DuinoDCX

You should be able to use something like https://github.com/schinken/PPMEncoder to generate the PPM signal.

Here are some examples of what I have done: https://github.com/lasselukkari/DuinoDCX https://github.com/lasselukkari/AirMonitor

Here is a tutorial that helps you to get started with creating a JS UI for the ESP32 using React: https://awot.net/en/guide/tutorial.html. If you can teach yourself React you will have plenty of ready made components to choose from. The advantage of using React will be that the internet is full of tutorials how to x with react as it is the most popular browser UI framework at the moment. The server on the Arduino will be the easy part. Here is an example of a more complicated project that has been built with the same stack as the tutorial uses: https://github.com/lasselukkari/DuinoDCX.

I have another software project where many people build their own hardware setup. So many users have had problems with their wiring that I got tired of debugging it for them one by one. This is why I created a simple sketch that can be used to verify the connections using a basic multimeter. You could do something similar to this just to verify that you have everything wired up as you expect including any possible cables: HardwareTest.ino

This is my own project that has the UI built with React and hosted directly on the ESP32: https://github.com/lasselukkari/DuinoDCX. You can try a demo of the UI here: http://duinodcx.herokuapp.com/