I’ve got a dual basket Ninja and I haven’t really found this to be the case for the past five years, most of which was cooking for two people

no issues with stink

perfectly sized for quickly cooking portions for two

does a better job for fries and tater tots and similar things than the oven

cleaning does suck a bit because the baskets barely fit in the sink and sometimes you gotta do that to scrub bc the dishwasher can’t get the baked on stuff off

sure you can’t fit two pounds of wings in it without needing to go toss 'em halfway through cooking, and yes it takes longer to cook and is more inconsistent if overloaded, but it can most definitely handle a large portion of food per basket. and if you’re cooking more than two portions, that’s what the oven is for

I gotta say I think you had the wrong use case / expectations and that there was some user error here. if appropriately loaded, it should never take longer to cook than the oven. it’s better convection and heats up faster due to size. it simply beats the oven at this. but it has a hard limitation on capacity