The apartment is as described, clean, and has everything you could need including AC even if the listing says otherwise. I stayed for a week and felt perfectly at home in the apartment - there was space for me to work out, work remotely, and even though the wifi needed to be reset once, it otherwise did not give me problems while on Zoom and loading "heavy" web pages.
The one thing I will say though is that Mortim Mortiz was not my favorite neighborhood to be in and I personally felt unsafe walking around in the evenings as a solo female traveler. I, fortunately, was working during the evenings most days, but even during the weekend, I opted out of staying out too late (past sunset) in order to not have to walk around at night in the neighborhood as much. I also Uber/ Bolt'd back to the apartment more than I would have otherwise. It was a sore point for me given Lisbon's nightlife and because Lisbon is otherwise known as one of the safest cities in the world, but do your own research - I could be more risk-averse than you are.
Still, 5 stars from me because the location of this unit is very clear in Maria's listing and the unit is as described otherwise.