I love this, but offering the product as a 3D print isn’t great. Sell me the guts and the STL, sure. But if I’m buying the whole thing, I would expect molded plastic. 3D prints are for enthusiasts or POC, not production

Overhead microwaves are terrible at venting. Lots of places don’t allow over the range microwaves over gas stoves in their building code. If you can afford to do so, consider getting a proper hood fan installed