You can get a notification on your phone when network is down, like discussed in this thread:
Nest Wifi will also measure bandwidth about once a day and show 30 days of history:
But you have no control over pull frequency or timestamp for any of them.
Appreciate your assistance, @olavrb.
@LaneCO68, thanks for posting. Instead of asking your Google Nest Wifi point or testing in the Google Home app, you can schedule a routine to monitor your network speed every day at specific hours. You just need to create a routine with an action asking about your internet speed and your Google Nest devices should automatically conduct it and provide you with results. Here's the support article on how to customize your routine.
Let me know if you have anything else to add.