October was a perfect month to visit Madrid, very warm and not too touristy! The flat feels like home with small cozy details, it has everything you need for a longer stay. Kitchen has everything you need for cooking (oil, spices etc.). There is a large supermarket (huge, also selling clothing/diapers etc) nearby and lots of small places to eat, bars and cafes. Hosts respond quickly if you have any questions and also live in the area.
Metro is very close. If you are traveling with a stroller, you can use metro stations with an elevator. They are clearly marked on the map. You can find many nice playgrounds nearby. Bus connection is also great. You can ask the hosts to pick you up from the airport with a child seat for 35e, night busses also run all through the night, easy to follow with online map. There is no elevator, so you have to walk almost all the way up, but it didn't bother us at all.
Note that this flat is located in Carabanchel, remote working-class district of Madrid with interesting history that made top third in Madrid crime statistics of 2021. The entrance to the building is right next to a noisy bar, there are no tourists, some homeless and drunk people are out and about. However as long as you mind your own business, you will be fine.
Overall, this is a spacious home to stay with family and I give it full points for this price-size-location combination.