Cats piss and poop

I’m a 21yo old student living in a region where pet supplies are extremely expensive (Nature's Miracle is literally $170+ here). I have no income and my parents won't help financially with the cats. Fisrt cat (4yo female spayed) She is very affectionate and sleeps in my room. Lately she has started peeing on my bed and the couch (which used to be in my room but is now in the living room) almost daily.

Second cat (1yo female unspayed) She barely goes into heat but she has started pooping and peeing outside the litter box occasionally. I clean the litter boxes daily and change the litter every 2-3 weeks I’ve tried moving the boxes they seem to use them perfectly when they are in my bedroom but I can't keep them there for hygiene reasons (I have asthma and yes I'm allergic to cats) I had to replace my mattress recently (which was so expensive so it’s now permanently wrapped in its original plastic cover to save it from forbidden salty yellow water. They eat and drink water perfectly fine they don't show any signs of stress or pain I play with them give them treats everything is more than good. I just used a vinegar and water mix to spray the bed/couch and now the entire house smells awful from the vinegar. How can I stop the 4yo from pissing on the couch/bed without locking her out of my room (without causing her stress)? and how can I stop the 1yo cat from pooping and pissing on floor? love my cats but I’m struggling to keep up with the cleaning and the smell. Any advice would mean the world to me thank you. Update my family said they'll give them away if they keep doing it please help if you have anything on mind.