It has Marlin 2.0.8.3-HW-V4.2.2-SW-V1.4.7G firmware which I am unable to flash over to other versions of Marlin for some reason, it just crashes.
My board is a 4.2.2. Obviously as indicated by the note above.
I don't mind changing the board out but I'm having a hard time finding any information on the 3 Max Neo and would rather not buy parts just to end up finding out that it's not going to work.
I would consider looking into Klipper. That would be a fantastic upgrade and there are plenty of videos on how to go about it. The documentation for the project is also easy to parse.
It was the first major upgrade I did to my Ender 3 that I got back in July. Way too spoiled by it at this point to go back to Marlin.