Scope of work would benefit from consulting a security company.

I think it looks good on the paper but to make a code compliant staircase you will have to call a stair company have them do the layout and they will tell you if you have room or not and give you what options you have. In here you wasting your time. With that said, they can probably fit 3' landing with 2 stairs going down and doing 90 degree turn with 10 stairs, that will set you at around 8"+ riser height, here in NJ you can have a riser height 8 1/4" and min thread depth 9" so it might just work. You have to check your local code and see what the stair requirement is for your area and work from there. Good luck

I have some suggestions if you are thinking budget friendly changes. Make a photo gallery with different size frames and arrange them parallel to the stairs, so you can enjoy each photo as you climb up. And for the area that will be on a level with your upper floor, try some pretty decal that will connect the photo gallery to upper level. And last, if you have budget add some beautiful hanging lights in the stairwell. Also think about repositioning your refrigerator.

Apologies, but couldn't follow the description.