This reads more like a rant then a review as others have said. A lot of your problems come from not knowing the programming space. There is comments and documentation, maybe a beginner programmer needs much more but a experienced one can read code like English and more comments just bog down the experience. Only complicated explainable sections should be commented. It may need more, but honestly the intersect code base is not complicated (from the parts ive read, im sure there are complicated parts).
Visual studio is completely free, you just tried to get the professional version which is 100% not needed and you probably wont even know the difference at your experience level. Hell, almost everything is free now, im not even sure I know the difference anymore.
You also argue that monogame is limited but dont say why? Seems like something you read somewhere and dont understand why.
The github patch point is somewhat true.
At the end of the day, a engine that requires no programming will be limited in what it can do. Rpg maker may be ahead in features as its been out longer. Not really a fault of intersect. If you want to make a unique game your going to have to program, or at least use visual scripting of some kind.