2. The missing angle you mentioned is not a big problem. How can the apartment be square now? In order to make rational use of every inch of space, it can be made into a square, and developers will not do it because there are the least square houses. So you can't buy a square apartment, but there are exceptions. I'm talking about the vast majority.
As for the problem of missing corners, I don't think it is big. Anyway, this letter is there. If you don't believe it, you won't believe it. If you must say so, this apartment is really difficult to handle.
Please accept my answer.