Wow, this is a very cool project. I already have the matrix lying around, as well as esp's etc.
I found your project when looking for some suggested code for home assistant, and darned, this is nice.
I have quite a few 'quindig uno' from quinled.info boards lying around for protection of led's, powersupply, esp etc.
So I was considering using that, but it uses RX or TX for communicating to the LED's, so can I change that in the software (instead of D2)?