Hi ! Go to settings - DEVICE INFO and check WIFI RSSI value when its connected.
If this value is higher than -80 dBm you might need to improve wifi coverage by adjusting your router or in any other way make the signal better.
The 5Ghz and 2.4Ghz will never overlap so that should not be a problem.
-67 / -71
II have tried with another router of 2.4 more distant and it seems not to give problem.