The only problem is that the camera would not survive the first time you use that oven. High power microwaves happily destroy all manner of electronics.
Shielding is straightforward; styropyro on YouTube made a ridiculously overpowered oven, 20 kW, was able to film the interior via a small hole, camera was basically fine.
IR and microwave wavelengths are nowhere even close to each other.
The grill in my microwave door lets through visible light. And the electronics already present in my microwave seem just fine.