Monitors to suit bird box

Just bought an RSPB bird box with camera to replace one that had all but fallen apart.

All set up outside and working with a small monitor in the kitchen. The previous birdbox's camera didn't provide sound (it was 17 years old).

The new one does provide sound but there's a distinct audible background buzzing on the small Nikkai TV monitor I bought all those years ago.

If I were to buy another monitor what sort of recommendations can anyone provide?

I don't need a TV monitor, just a monitor plain and simple. It needs to be small. The current on has a 7-inch screen which id just fine.