I would definitely recommend Hugo & Silvia’s flat.
It is very clean and exactly as pictured. The view over the river is even better than in the pictures.
Hugo was an amazing host and gave us an in depth tour of the flat. He was also able to offer advice on local/regional transport and always available to contact through airbnb or whatsapp.
A few notes about the flat:
You have an amazing view over Alfama from both of the living room's windows, both windows can be fully opened and you can even step outside on a tiny balcony, all windows can be completely closed with shutters (in case you are worried about sunlight creeping in), the flat is quiet at night, many of Lisbon's sights are within walking distance (10-30mins), the tram stops nearby, the flat didn't get hot but there is an AC in case it does, the kitchen is equipped with all cooking accessories (pots, pans, bottle openers, fridge/freezer... no cooking oil but salt and pepper were present), the flat's TV has NETFLIX, Wi-Fi is quick, bathroom water pressure is excellent (lots of towels and rolls of toilet paper were provided), the flat features a heavy lock for safety...
Please note that Lisbon is called the city of seven hills for a reason, expect steep stairs and some hills. The flat is on the 3rd floor.
All in all a great stay.