Salam Sidi
Salam
The Arabic word 'Qibla' is formed from its root word 'QAF-BA-LAM' and means to face or front something, to advance, to encounter or to confront face to face. It forms words such as 'istaqbalahu' which means that he faced him or it, that he turned his face towards him or it or indeed met him.
Other word derivates are also formed such as 'qubalatahu' which means opposite to, in a position so as to face him or it. Other words are also formed which imply a direction, point, place or something which is in front of another thing.
The Quran consistently uses the word 'Qibla' in the context of a direction of devotion
Yes, Yes, and yes

I agree with all that!
or prayer (2:142, 2:143, 2:144, 2:145, 2:145, 2:145, 10:87)
AQ-10:087
"And We inspired Moses and his brother with this Message: "Provide houses for your people in Egypt, make your houses into direction (Arabic: Qiblatan) to establish prayers: and give glad tidings to those who believe!"
About 2:142-145
2:142
Literal: The ignorant/foolish from the people will say: "What turned them away from their direction ,which they were on it?" Say: "To God the sunrise/east and the sunset/west, He guides whom He wills/wants to a straight/direct road/way."
This aya actually says no matter east or west, Alsiraat almustaqeem (the right path) is not bound to any cardinal direction. I think it is about direction in faith. So the fool who dont know what the right path is about will ask why those people changed their faith?
2:143
Literal: And like that We made you a moderate/reasonable nation to be witnesses on the people, and the messenger be witness on you, and We did not make the direction that you were on it, except to know who follows the messenger from who returns on his two heels , and that truly big/great except on those who God guided, and God was not to waste your faith/belief, that God (is) with the people merciful/compassionate , most merciful .So, by telling the people that its not about any direction on the compass and showing them the right path (in 2:142) God made them a reasonable/moderate nation.
I dont think that the direction of Salat is so hard to follow that the direction in particular will be the criterion for the prophet to know who is with him and who is not. All muslims pray towards Kaaba but they all follow hadeeth and sunna and all kind of traditions as well, so how are they following the rasool? That is barely something hard except for the nonbelievers. However what is hard for the nonbelievers is to follow Abrahams religion, the straight path.
2:144
Literal: We have seen/understood your face turning around in the sky, so We will turn/enable/appoint you a direction you accept/approve it, so turn your face towards the Mosque (masjid) the Forbidden/Respected/Sacred and wherever you were so turn your faces towards it, and that those who were given The Book they know that it is the truth from their Lord, and that God is not with neglecting/disregarding about what they make/do . God is talking about the confused believer (messenger or not). God is telling this confused believer to turn his/her face towards "Masjid Alharam". Turning the face towards something is not literal here because God told us earlier that its not about physical directions. Its about facing life, face life with masjud alharam in focus, in other words live like Abraham did since he established masjid alharam.
2:145
Literal: And if you gave/came (those who were given The Book with each/every verse/evidence they would not followed your direction, and you are not with following their direction, and some of them not with following the direction of some, and if you followed their self attractions for desires from after what came to you from the knowledge , that you are then from the unjust/oppressors. Here it becomes clear that Qibla is not about any direction for salat. whatever evidence you bring to them they still wont follow your way (alsirat almustaqeem as previous). They follow other ways/faiths in life according to their desires.
Honestly to claim that those ayas has anything to do with salat and its direction requires some hadeethly imagination
10:87
Literal: And We inspired/transmitted to Moses and his brother that you reside/establish houses/homes to your people/nation by a city/border/region/Egypt, and make your houses/homes direction, and keep up the prayers, and announce good news to the believers.bani Israel were in trouble and they asked God for help. This aya is what God told them to do as solution. Make yourself homes/dwellings in this place (misr) where you are oppressed but make your houses even qiblahs. I am not sure of what this means, I think to make the houses a place where they can take refuge, remember God and maintain alsiraat almustaqeem since they were not allowed to do this freely in misr. And ofcourse maintain salat. But maintaining salat there has nothing to do with their houses being qiblahs.
Peace!