landscape company who specializes in pools/backyard kitchens. call them.

but yeah, you can't just shrink a pool. It would need to be completely redone. You'd pay for a new pool, plus the added expense of demoing that one.

find another place for the outdoor kitchen area. (and if you want electrical and water, that's what it will be. you'll need to tap into the sewer line of the drain if you want water)

Wooden decking instead of pavers is a big downgrade, especially around a pool. I'd keep the pool as it is, or remove it completely. If you want to remove it completely, you might consider moving instead.

You can build a new pool inside an old pool, but I would not be comfortable with it.

As a contractor, I would be relying on a solid build to set my new structure and quite frankly, I don't trust and I don't know the conditions (mostly soil) and or the methods when the original pool was built.

Removing the old structure and starting fresh allows for testing of soil, finding a new location for a new pool to work with a new plan rather than being confined to one area to work with.

A landscape architect that deals with pool design or a pool company that has in house designers that work with landscape contractors is someone to look for.

Wood decking around a pool is not a good idea. It's a lot more maintenance than pavers or natural stone. Even the composite decking is not good. Support framing should have a minimum of 10" of air space for proper ventilation despite having pressure treated framing.

Yikes why did you buy this property!? Pools and WOOD are not a lasting mix. I see two patio areas. Make them work. Either has the electricity you seek. What does the rest of the lot look like? Is there yard to expand the far patio?

I would consider hiring a landscape architect. He or she would be able to give you advice on your pool, barbecue area, etc. I agree with the other posters - resizing a pool isn't something I've ever seen done before. Good luck!