The App has a Global Settings to Pause Notifications for All Devices, but it can’t be applied to select individual devices. In the Home Page Device List, press the 
Bell icon in the upper right. The Pause Notifications options will appear for you to select.
If you want to pause notifications for only select devices for a specified time, you are going to have to get creative. I do this by using a Wyze Plug to pause Notifications when I do Yard Work. I have a Wyze Plug that has nothing plugged into it. Its only purpose is as an Alexa Relay. It is named Yard Cams Plug. I tell Alexa “Turn Off Yard Cams Plug for 1 Hour”. When the Plug Turns Off, a Wyze Rule is triggered to turn off notifications on my Yard Cams. After an hour, Alexa turns the plug back on and another Wyze Rule enables the notifications on those same cams.