I am sorry to hear that you are feeling a bit frustrated with learning to play the guitar. As others have said, we all go through this. But that being said, it still is a sucky feeling.
I am convinced that learning to play an instrument is like learning a new language, and ask any adult who has taken up new languages and become fluent in it, it is a long road that takes time, years, so patience is a key.
I do have an honest question, and please don't be offended by it. That is not my intent at all. You write about multiple courses you have studied from and a little course paralysis in deciding what to study from so many availableboptions. So my question is, how many courses/books have you completed from start to finish, mastering the material presented in the content of the course, before moving on to the next course?
Also, how many songs do you know, even at a basic level, and how often do you play them for enjoyment? I know that personally I can spend too much time on technique building, working on course materials, etc., and forget about why I am studying the guitar in the first place, which is to play music which I enjoy. I feel that one should always be working on a song as part of ones practice regime.
Hang in there!