You don't put a fire pit too close to the house and certainly not under a porch.

To screen in the lower level, there has to be some sort of screening between the levels. That collects junk and gets nasty.

My parents had a patio under a deck and nobody ever used the patio. It was oddly basementy, even though it was a walk-out basement like yours.

Agree with screened porch on upper level unless you make the deck floor solid in which case it would need to be pitched slightly for runoff. Would be careful with the stairs. My neighbor has that set up and they’re quite steep. See if you can add a landing.

Agree with Mad_gallica--it's an unpleasant space--too much like a basement.

Do you use the patio now? I'd put the funds into the space you'll use the most. A stairway with landing and the new surface first. I'd then consider expanding the upper deck area.

I would not want stairs blocking the view of the yard. Bring them down along the house towards the chimney and then a landing as suggested over the AC and a 180 down to where the ladder is.

Thanks all for the great input. We love the sun on the deck and brings lots of light into our home so would hate to screen that in. We do use the patio (under the deck) at night to sit outside, agree it would need a costly makeover to be comfortable and screened in. I think we'll start with the stairs + landing down to a stone/concrete patio and go from there. If anyone can mock this up so I can visualize, that'd be awesome!