A really nice video;-)
Well you said the configuration is for retropie 3.
I forgot to write. Under 2.6 and below it is indeed technically work, but needs to be set up differently.
For what “overlay0_descs = 0” in the overlay config I do not right now.
I have the config simply copied from another overlay and adapted to the filename. To my knowledge you can thus define for touchscreen displays overlay buttons.
Here it is described in detail: