iPad connects sporadically to WiFi

I have an Ipad Air (4th gen) and a iPad (9th gen).  The 9th gen iPad has trouble staying connected to WiFi. In the morning my wife has to turn off WiFi on the 9th gen and turn it back on again for it to connect to WiFi. My iPad Air does not have this same problem. And sometimes during the day my wife has to do this a time or two. I've worked with Apple Support and no resolution yet via them. i can't see how these iPads could behave so differently.