Thanks for reaching out and for providing detailed information on your issue and the steps that you've done — these are of great help!
You can do a sequential reboot. First, unplug your Nest Hub 2nd gen for 30 seconds, then do the same thing to your Wi-Fi router to refresh both devices and your Wi-Fi signal. Once it’s back on, observe if it will do the same thing.
Let me know how it goes.
Apologize for the delays. Chiming in to ensure everything is covered here. Could you tell us the firmware version of your Nest Hub (2nd gen). You can follow the steps below or visit this link to learn more.
Keep us posted.