Hmm, I see. My question is, why do chickens need that much space in a coop if they'll be using it only when sleeping? Let's say we close the door only at night when they are already sleeping and open at dawn, would that make any difference?
So if I add an extra 1 meter perch, along with the ones inside the house, it would be enough space in my mind.
As for the openness of the coop, some summer nights can be really hot. During colder winters it's easy to cover those windows so the chickens feel more tucked in and warmer.
I've offered advice. I've offered explanation. You seem intent on doing what you want to do, regardless. Still, I'll make one last effort.
First, when the weather is fine, your birds may want to sleep outside in the run. Then you don't need any house space at all.
The reason the house exists is for when the weather is NOT fine, and they may be cooped up there for days. Space is a social lubricant, too many birds in too small a space leads to stress and behavioral problems - feather pulling, aggressive fighting for dominance, etc
Second, Portugal doesn't often get "really hot". Lisbon, for instance has a high of around 83F in July, on average. Talk to me about really hot when its over 100F (38C) for 60, 80 days out of 100, not the 5 or 7 whioch made world news back in 2018. You have brief heat waves, when the birds will absolutely not want to sleep in the house, yes, and should not be forced into it.
Neither does Portugal get "really cold". Blocking their ventilation to protect them from lows in the 35F (1C) range is a recipe for disaster. You need ventilation, about 1 sq ft per bird, to help move moist, ammonia laden air out to avoid respiratory illnesses and the like. Birds are naturally equipped with down blankets. If they are dry and not drafty, a fully feather bird can easily take temps of -20F or lower (-30C) - they aren't cold sensitive the way we humans are, and should not be treated like humans with our much more narrow comfort zone.
Based on my readings, Portugal gets a LOT of rain compared to many places, mostly in winter - similar to my own 59" a year. Ensuring birds have a place to get away from cool, windy rain - a source of potential frost bite - is the reason you want a hen house with adequate space.
But you do you - I'm stepping off.