My streak of bad variance continues after an other session in which nothing, NOTHING hits my cards good, or I get coolered on the River.

The possibility of busting at 2NL is starting to loom. Not immediately, as I have still around 14BI, but that I am going under the usual "bankroll" at 2NL is getting to me, like I am ashamed. I have plenty of money in my bank account to replenish my BR... but it's more like I am unable to beat that damn game anymore... or I was just running good before, and now my lack of skill is showing. From 6-7bb/100 two years ago... I am getting to this.

Did it ever happen to you guys, to go bust at 2NL? Did you feel bad about it?

As it's "getting to you" and you have the spare cash I would strongly recommend topping up to a better BR to avoid playing scared poker. I speak from experience! I'd also suggest taking a couple days break from playing poker and use it to go through your sessions and find some aspects to improve upon, GL!

Rake has gone up to the point where it wouldn't be surprising if this winrate 2 years ago means you're break even or losing now. Something similar has happened to me, I didn't feel bad about it because that wouldn't do anything productive.

You might want to examine how much rake you've paid and how much that's chipping away at you. You might benefit from moving up to 5NL just because of rake. OP should move down to 1NL?

It is nigh impossible to bust at NL2, because real world money is so valuable compared to a "bankroll" in the micros. 50BI = $100. That's 2 decent bottles of wine. It is one night drinking in a bar. It might not get you a decent dinner + movie with a nice guy/gal. This isn't to say the smallest stakes are meaningless, if it matters to you it matters. However, BRM is about protecting a professional gambler from losses that he can't easily replace. It has to do with goals. In the case of a pro gambler, it is the difference between being in action and having to go find a day job. At stakes where you skip lunch and have 3-5 additional buyins, busto is impossible. Unhappy? That can happen.

It gets down to this. Why do you play poker? If it is to challenge yourself to beat the game, then you're in a rough stretch. However, don't let the account balance add to the misery. If you can easily afford to play and lose (sounds like you can), then don't care at all about BRM.
I'd feel bad about playing badly. Even that is self-imposed misery.

This is like left pocket/right pocket accounting. If our OP has $100k in his checking account (or $500) and $9 in his Stars player bank, is he desperately short, or infinitely rolled? The pain point is about redepositing? That's a mental leak. He's gloriously over-rolled.
This is always good and the true gift of a downswing. So few people improve their games while winning.

This is a true issue. It could be our OP is playing the same really decent 2NL poker, and game changes mean that his old win rate is really low or 0. The lower your WR, the more often and bigger your downers.
This is a great way to look at life.
I don't play these games. There are stakes where this is true (live $2/$4 LHE is raked so badly that $4/$8 is actually better, even with the same skills). Sort of doubt online NL is the same, but no experience.

Poker is a game of decisions. My advice to our OP would be to look at hands to find if there are decisions that could be improved. If most of his decisions are really good, is rake the issue? Getting someone he trusts to review some hands could be just the thing. As for feeling bad? It is a fun hobby. Take a break. Learn some stuff. Even if he doesn't win, the accomplishment of getting better is worth something. This all could be bad luck, but use that as an opportunity to improve.

I have looked into the rake for 2NL at Poker Stars: 3.50% of all pots won post-flop, capped at 30c for all player caps:

(2nd to 4th row: 2 pl -3-4 pl -5+ pl)

$0.01/$0.02 3.50% $0.30 $0.30 $0.30

$0.02/$0.05 4.15% $0.50 $0.50 $1.00

$0.05/$0.10 4.50% $0.50 $1.00 $1.50

The best vid I'd suggest watching is Johnathan little on beating 6max nl zoom micros. I haven't found anything that will help you beat up to nl10z more than that. It's not even a huge time investment either and just seeing how he plays and thinks about hands will help a ton. He doesn't have many bluffs (which is fine add those in later when you're beating at least 10nlz) and throws balance out the window which isn't needed a ton at these stakes with such large player pools

Well I struck a Quad on playing my twice-a-day The Deal tonight, and won $30. This doubled my effective bankroll. Should I call this a form of rakeback?

Had also a good run tonight. My aim was more to cut my leaks, force myself to avoid needlessly tight situations and fold when I read that I was behind with next to-no equity. Aside of a few tricky spots, it was a success.

I did not find this video on YT when searching for Jonathan Little. Is it on another site?

He has his own training site, FloatTheTurn, so it might be on there. He often does free webinars, but I think FTT costs $10 a month for a subscription.

I'm 90% sure it's on YouTube lemme try find it for you

E/ I can't find it anywhere D: it was him doing a play and explain for 5nl and just the way he presented it was really really good for a micro stakes beginner