Afaik you cannot escape from having wifi problem on this non-branded android device because most of them are using knock-off wifi dongle.

I repaired a few of the units and some of the units are really terrible in terms of the quality of the assembly. You can either take apart the unit and readjust the position of the wifi dongle so it stays closer to the top of the unit.It works sometimes.

You can try using the ethernet LAN. Its plug and play and does not have connection issues.