My firmware won't run both the two line display and the nextion display. When I plug in the two line display I don't see proper characters.
What this suggests to me is that if you can see the 2 line display you need different settings in the firmware to allow the nextion display to work.
I have stl files for the 2.8 3.2 and 3.5 versions of the display if you want to print them.
dave
k0mbt
_Dave_ AD0B