Not airfryer related but we always cook beef in our slow cooker Cook on Max 4.5/5hrs cut a few carrots in big chunks place in the bottom sit joint on top No liquid required Leave alone,once cooked /cool/place in fridge overnight then ready to slice If needing it hot place slices into a oven tray cover with heated gravy place in preheated oven then serve The best/moist/tasty beef ever,every time,same cooking method with a leg of lamb maybe less cooking time than the beef depending how you like it,ours 3.5/4hrs
I tried a silverside joint in the slow cooker but it was really dry, I think it would have been best totally covered with stock rather than an inch at the bottom.
We Dont do that no need our method works perfect every time
Our slow cooker is a simple Asda 6 ltr cheapy with simple high low settings (use high)
I suspect its the cut as we only use the cheaper roasting joint
Give that ago you will be amazed how well it cooks