Hello to everyone reading this. I've been playing poker for about a year now. My journey started with micro SNGs and I was doing pretty well in them built a bankroll from 0 and got up all the to about 100$. Had to withdraw some money couple of times and was mainly moving up and down tried different formats played PLO up to 10PLO (thought my 20buyin bankroll management was good enough) and somehow ended up busting that all the way down to 150$. Last couple of months this has been my story : Get to 150$ play either SNGs or cashgame, go all the way to 200-300$ somehow manage to lose it down to 150$ and repeat. Sounds like every losing player's story.
Today I pretty much hit nearly the bottom since these couple of months and my bankroll went all the way down to 90$ playing NLHE. I'm honestly without words about how this happened. For anyone reading this you would think I'm just a clueless guy who can't even beat 2NL and you are apparently right. There is however another side to this. I've spent these last couple of months watching runitonce videos pretty much every day. I can without a doubt say I've watched way more than 100 videos of the essential content excluding a lot of youtube videos. My assumption was that anyone with a little brain and good preflop opening ranges can beat at least 2NL. Well I'm actually proven losing player all the way down to 2NL right with over 50k hands at 5NL and bunch of untracked play as well. I'm just completely lost. I go through phases of "Oh it's just variance , you will grind it out" and then to "How retarded do you need to be to not be able to beat 5NL and 10NL after this amount of time spent studying poker?". I do know I have certain potentially big leaks such as not defending sb/button/cutoff wide enough (F3B of 70% 61% 58%) this is however I feel like a bit of variance and sample size problem. Looking at my defending ranges I don't think I fold 70%.I still think that even with such leaks one should beat the micros with ease as long as he plays well postflop which I think I still do.

So far I've watched the following on runitonce :
Every single Cameron Couch, Sam Lang,Lucas Greenwood, Felipe Boianovsky, James Hudson, Phil Galfond (essential) and half of Steve Paul videos.
I did not watch any of these videos without paying careful attention so most of the concepts I've seen I try to implement in my game if possible.

The purpose of this thread? Well I didn't just come here to cry and tell my sad story. I'm looking for anyone who has any idea what he is doing to hopefully help me. I could record one of my sessions and upload it somewhere or you could perhaps sweat me live. At this point I just don't know what to do anymore, keep playing. trying to get out of the downswing or just start studying even harder. Quitting is not an option for me. Potential database review is welcome as well although I doubt there are too many generous people offering such help.

TLDR: I think I know something about poker but results show I suck so I need help.