Cannot find WiFi until rebooted

My MAX BR1 Pro 5G is usually connected to a WiFi connection with Cellular as a back up.

After a day or 2, the WiFi conenction fails and the router swaps to cellular.

Every time I have noticed thiis, when I login to the router in says ‘No WiFi avaialble’ but if I check ,on my phone, WiFi conenctions are available.

I then reboot the router, it finds the WiFi and connects OK

Any idea what could be going wrong?

Is there a way to get an alert if the WiFi conenction fails?

TIA

Can anyone help?