Cat Smell Strong After Cleaning

Bit of background. My roommates and I had 2 cats between the three of us, and last October my third roommate's family was moving across the country and asked us to take the cat during the move, then fly with her out there. Unfortunately, new cat absolutely refused to get along with our prior two, and had to be locked in my roommate's room for what was supposed to be three weeks max. There's an attached bathroom in there, where the litter box was placed. Due to finances and unreliable family members on my roommates side, the three weeks has turned to three months, and we have tried all the textbook ways to introduce a new cat so she wasn't locked up the whole time, and she just isn't having it.

Now, said roommate doesnt have the best cleanliness habits on the best of days, and after all that time I started having respiratory issues from across the hall with the door shut, and the cat was placed at another relatives house for the weekend while we clean.

Problem is thus: We have vacuumed, swept, mopped, and Lysoled every surface in the room, and it still smells of cat. I have taken a black light to the room at night and cannot find any locations where it luminizes, and the floor is made of vinyl panels. I recently applied nature's miracle over the entire floor, and still no progress. It's better BY FAR, but the room is a rental for school and my roommate doesnt intend on being here next year, so we need to get this cleaned fast. Any and all suggestions needed.

Currently, our only options are to rehome her or place her at a shelter, neither of which my roommate is willing to do, because the family has had her for over a decade.

The best product I've found for getting rid of cat smell is one that doesn't even advertise for that purpose. Of course, it doesn't do all the wonderful things it claims, but I keep buying it because I can use it for cleaning floors, bedding, and everything in between. Advanage cleaner.

Don't use Lysol. Lysol (and other similar cleaners) contains phenols which are known to be toxic to cats.

Can you open the windows to air out the room? Are there any soft furnishings in the room (sofa, cushions, etc)? Those can absorb odors so you need to wash / treat them with cleaner too.

Is it a urine smell or cat food smell?

No more Lysol, understood.
And I had the room airing out yesterday, windows open and fan on. Not my room, so I can't say what the progress is on that.

As for fabrics, just the bed and sheets, and obviously the closet and clothes. He's already washed the bedsheets.

Is it a strong ammonia smell, a dirty litter smell, a poopy smell, etc.?