I just bought RPI4 and 4.3 display (https://www.waveshare.com/4.3inch-dsi-lcd.htm). I attached display as required but wasn't able to get wifi connected. I noticed that
sudo iwlist wlan0 scan shows some networks but just strongest ones. I was searching for solution and I found this: https://www.enricozini.org/blog/2019/himblick/raspberry-pi-4-loses-wifi-at-2560x1440-screen-resolution/ ... so I unscrewed display and placed display and RPI4 on the desk as far as possible and wifi started to work.
Does anyone encountered that problem? It looks like wifi signal is being jammed but I do not know how to approach that problem.