It really depends on the climate of where your home is. I would not spend money on an outdoor kitchen in a colder climate. Reverse that for the fireplace.

i built alot of outdoor kitchens i think they are a pain to keep clean and though ive never seen snakes in one i always wonder how you keep them and rats out im planning on a built in grill and brick oven myself

It depends on your habits, climate, location, etc. I have no use for a fireplace, or fire pit, but cook outside, as often, or more, than I cook inside.

If I could only have one I'd go for the kitchen. If you can do both I'd definitely go for that option. You could use the fireplace for a pizza oven imo.