WiFi gets slow, turning airplane mode on and back off temporarily fixes it

After a half hour or so of semi-continuous use, my iPad seems to stop loading data over WiFi. The ‘network activity’ icon in the upper right will spin, but nothing loads. Doesn’t seem to matter what application I’m using. I can switch to other applications that don’t use network data and the iPad is responsive.

Turning airplane mode on for ~30s seems to temporarily fix it. So does switching to cellular data.

I have this problem on my home network and on public networks. I don’t have the same issues with a work PC. I get good throughout on the iPad as reported by fast.com.

I’ve tried resetting network settings on the iPad. I normally use Google DNS, but have also tried OpenDNS and my ISP’s servers. I’ve also tried clearing safari’s cache and killing all other open apps. I’m running iOS 12.3.1.

Anyone else seen this? (& more important, have you found a persistent fix?)