This problem started with the update to iOS 16.x.x. I spoke with Apple support about it and they shirked it off with "your iPad is too old, that is the problem". Yet, my iPad isn't too old for me. It's not the latest, but it supports the latest OS and up until 16.x.x it worked perfectly. We tried everything we could imagine, other routers, reconfiguring network, resetting the entire device, nothing solves it because it's an obvious bug in the OS. It also broke streaming on Netflix and other streaming apps. It's not a function of bandwidth as all of those run steady and fast as always at nearly 1 Gbps / 1 Gbps. I contemplated doing what I suspect Apple wants, and just buying a new device even though this one is perfectly fine prior to their update, but I keep checking and looking for a solution. It's interesting to see that even people with newer devices are experiencing the same. So, maybe they'll eventually acknowledge the bug and fix it.
Restarting the iPad temporarily fixes the problem for me as well.
Oh, and we have much older Apple devices that run fine.