It is not clear how to navigate/change/upload MilkDrop presets from the GUI. I am trying the online version at https://webamp.org. Is that documented somewhere?

Sometimes uses tabs. Change to 2 spaces per tab.

Is it possible to share your build configurations to build it ourselves ? Would like to have the newest nwjs version

For ESP32 can use the second core as the webserver and prevent delays in response.
https://randomnerdtutorials.com/esp32-dual-core-arduino-ide/
Might add a different example for ESP32 or add this as macros to the current example.

The method WordList.QuerySuggest.Phonet has two nested loops that query for entries from a PhoneTable that have rules starting with a given character. Indexing these entries in the table by the first rule character may have a positive impact on performance.

In the Readme you have images with come sample commands

For those of us that are lazy (me) or error prone to making mistakes whilst typing (also me) please add in the example code alongside the screenshots