iPad 9th generation connects to wifi only when it’s charging

I bought my iPad 9 recently and it was perfectly fine and only 2 days ago I noticed that it keeps knocking off home WiFi only when it’s locked and it completely disappears, so I had to turn off ( not just restart) and turn it back on to have home WiFi appear again and get connected.

and only today that I noticed that it can be connected to the WiFi with no issues as long as it’s connected to the charger (after going through all the tips and network restarting and changing the WiFi frequency and even doing a firmware update on the router).

this happens only with the home WiFi, I tried hotspot and other WiFi networks and it didn’t act like that, so does anyone has an explanation for this, is it a hardware or a software issue ?