does everyone who 'cat proofs' their garden have acres of land and pots of cash to spend on shed like cat runs

i live in a 2 bedroomed, 2nd floor flat right in the middle of quite a busy city and i keep my cat in 24 hours 7 days a week, which she is more than happy with, i've had her since 3 months old so she doesnt know any different. I do have a bit of a 'garden' but it's more of a patio area which is probably about 6 ft by 6ft, maybe a tiny bit more.

I would love to have a small enclosure [it would have to be quite small in height as well, otherwise i risk blocking other peoples windows,] outside so my cat could laze in the sun. But i cant find any, anywhere that even come close to fitting in my space.

anyone know of any