I have three iPads and updated one them to 13.3 and it ran my QU app fine operating the mixer. Also tested it with the DBX 360 app operating a DSP and Safari operated my Soundcraft Ui fine.
Didn’t get a real feel for battery life or wifi range differences (if any) with the testing.
I use a hidden SSID on my wifi and the iPads have always taken maybe a minute to connect and fully come on line with the wifi connection.
Connection to a open SSID is just a few seconds.
The connection times seems about the same as the iPads running the older iOS 12.4
For what it’s worth my iPads are all AIR2 models.