@yams Yes, but it is fraught with danger:

LilyGO sells these as a ready-made user device with a firmware uploaded to it, rather less than a typical Arduino experimenter kit! Hard to find the original as-shipped source code for Arduino 2.x.x Hard to "nail-down" the LilyGO GitHub repository for your EXACT board Sure you can create your own program, but converting back to as-shipped might be difficult due to ever-shifting libraries and other 'dependancies'
(This third party firmware repository may help: