I have the air fryer attachment for the 6-qt Instant Pot. It works OK, but it isn't really big enough to cook an entire chicken or anything like that. Manu of the air fryers can fit a whole chicken. However, it did a nice job on a bone-in chicken breast. If I was in the market for an InstantPot I'd buy the 8 qt Evo Plus. My first Instant Pot was a 6 qt and I found that my recipes were suited for an 8 qt. The thing about pressure cooking is you can only fill the pot about 2/3 of capacity. If you overfill it, the pot won't reach full pressure.
I'd also stay away from their slow cookers and oven-type things. Their core competency is pressure cookers and they have designed one that works well. Their first foray into slow cookers caught fire. I'd get a Cuisinart or Cock Pot brand slow cooker. Besides, after you start using your pressure cooker you won't use the slow cooker very much.