I'm testing now with the following platforms/browsers:
Windows - Edge
Windows - Firefox
Android - Bing App
Android - Samsung Internet App (Chromium?)
Strangely enough, 'only' Android- Samsung Internet App managed to load the past logs quickly or delete apps/drivers. However, device discovery still fails with it and the notifications icon still says 'hub unreachable' when using it.
A lot of functionality seems to be broken under Microsoft Edge, Firefox, and Bing - even though all those platforms worked fine a few months ago before the latest firmware changes. I'm not sure why loading of past logs is just so slow when using anything but chromium based browsers.
I'm starting to wonder whether if chrome is the only supported browser now and larger zwave networks just are especially buggy with current hubitat.
Every browser does generate the 'hub unreachable' notification and there is no clue what that means as the hub is obviously still on the network and even reachable via the mobile app.
I've rebooted and upgraded firmware for weeks, shutdown, toggled zwave on/off, doesn't help.
You might like to DISABLE the custom drivers and/ or Apps, one by one, testing responsiveness as you work your way through them. It’s not going to be quick though.
Perhaps a Hub update tidied up some wonky code that was irrelevant before and now it’s causing issues.
As @stephack mentioned, you should reach out to support