On recent macOS updates I’ve sometimes experienced that my Mac will disconnect from my home wifi after several hours and refuse to reconnect. It’s not a password issue, just failure to connect to network. Restart the Mac and gone. My home wifi is AirPort Extreme (last gen) based and usually rock stable so this is definitely related to the updates. I have no idea why a restart would “fix” it. Since there is a lot of common code used between macOS and iOS, especially for stuff like network layer, I wonder if these issues could be related. Have you tried a forced restart of your iPhone/iPad?