I'm back and i watched the whole video. This is interesting because watching you i see you understand the game very well. You make threats, you see threats. Now the big question is how then do you lose?
Well, I think you don't focus throughout the game. There is always a blackout for a move or two that costs you.
Maybe the time or something. In one part of the video, you mentioned after 20 mins you don't concentrate again like that. Maybe blitz is too fast for you. Maybe you also need to sharpen those openings. It makes it easier for stronger players to beserk and go Scot free