I dont think his g5 is a massive mistake , he already got a completely lost position cos he's so cramped. If he doesnt do something - anything , youre just going to advance pawns on the k-side and win easily.
It is a Maroczy Bind . I dont know a fat lot about the Dragon, but I believe it includes d6, not e6. dont take my word for it.
I think you played well
It was pretty clear that black did not know how to handle the opening and white seized the weaknesses in black's camp. Maybe there are some minor improvements for white, but nothing earth shattering.
14. ... Bxc3+ seems wrong. Giving doubled pawns is not worth the dark square weakness.
"16. a4 prevents b5" Not sure why you are trying to prevent your opponent from hanging a pawn. I would have preferred 16. e5 to prevent black from playing e5 himself. 16. e5 lets black try to get his knight to f5, but white can still control that square with g4.
16. ... f5. This is suicide. 16. ... e5 would have been much better to try to free the position.
20. fxg5. Not sure this is necessary. Your opponent's pieces can't move, so I'd just play 20. g3. If he plays 20. ... g4 you have 21. h3 opening the h-file. Keeping the pawn on f4 keeps his knight out of g5. I'd be looking at putting my bishop on the long diagonal and playing Rb1. Of course, at this point, winning plans for white are not hard to find, but it's good to keep in mind allowing no counterplay
I am not very familiar with this opening, so please let me know what you think and also where my opponent or I could have made better moves.
Some notes and a small number of variations in the move list. Thanks for taking the time to look.