Does it need calibration? OLED BUG? Home assistant? (Airgradient V4.0)

I assembled a DIY Airgradient basic V4.0, and have a few questions:

• Do any of the sensors need calibration?
  • If so, how to calibrate each sensor?
  • How often to calibrate each sensor?
• As I want to keep data locally, I connected home assistant to it via the airgradient integration, why does it show PM0.3/1/2.5/10 in HA? The PMS5003 sensor should only measure 1/2.5/10 right? Should I disable the PM0.3 reading?
• I soldered the OLED display as per the guide, it works initially and goes through first steps but it gets stuck at "Connecting to WiFi" even though it connects and tracks data fine, is this known? Serial monitor also works as intended. I ordered the exact display recommended in the guide
• Is it better to mount on a wall or can it stay on the desk?