I just tried with the Buster release 250, at first it didn’t worked (it didn’t built the access point) then i plugged the ethernet cable and finaly got it to connect to my network.
I then successfully linked the pi with my Wifi but this only worked with the 5Ghz network, no chance to connect to the 2.4Ghz network which might be the reason why max2play couldn’t built an access point.
I tried with a raspbian buster image, clean install, and got the same troubles. I was only able to connect to the 5Ghz network.
So it might be that the waveshare screen is jamming the 2.4Ghz network in some ways.
Anyway, i’m going to stick with this setup for the time, seems to work well.