i believe if he took, en passant (in passing) that would have been a bigger blunder, because it opens up that file to the rooks, and when the king is in that file, its even worse.

Chess is so easy to get better than 99% of the people.
Mostly because they haven't learned chess at all.

But, after that, if you don't have a mind for chess, you really can't go anywhere.
The upper levels of chess are not just good at it, they are brilliant at it.
No amount of time in study or practice can make up for it.