QJo

I fold preflop QJo on UTG. On flop I prefer cbet than check-raise. On turn vs your nearly pot size bet he continue here with strong hands like sets and he can push all in there.

What story are you telling? Even though it is NL2, you need a story to bluff.
Let's get into villain shoes and consider you a TAG player.

You open from UTG. For villain, your range can be JTs+, QTs+, KT+, ATo+, A7s+, 77+.
Flop: What, from that would you check in a dry board? What would you check-raise? Keep this in mind...
Turn: What K hands are in your flop check-raise range? I don't think you have a check-raise range for that flop, even less any with a K. More, what hand that check raised (being ahead on flop) would fire pot on that board? Any hand strong enough for a check-raise flop would lose value on turn. You fired pot without need for protection, and no valuebet range.
River: You are lucky to get something for SD. Your story wouldn't convince me to fold Tx most of the times.

I played around with the solver and it actually does c/r quite a bit on the flop (interestingly, it would c-bet this board, but only check and then continue).
The issue is, however, that the solver doesn't have MP coldcalls, so I used CO or BTN coldcalls as a starting range.

Interestingly, the solver would bet all QJ with Qh in this spot and check all others on the river. I'm not yet able to really fully wrap my head around this:

I think that the board is generally much better for the coldcaller, who will often have pockets <TT and suited connectors, but less of big broadway cards (much make up a large portion of my range) -> hence to no c-bet-strategy on this board. Assuming that I never c-bet, I have to have bluffs, and for that, QJ and KJ are most probably the best suited hands.

You may disagree, but actually your post asked me to review my story again, and the more I think about it, the more it makes sense and I like this hand from a GTO standpoint.
That being said, since this is 2NL - it's probably badly played on this limit

Disclaimer: I never used GTO, so my interpretation of it can be wrong.

GTO is designed to reduce vaillain's exploitability on you. For that, it mixes bluff and value hands. Considering you play 100% GTO the money you may lose when you don't succed in this bluff is more than compensated when you have a valuable hand in this spot.
As I don't think anyone plays 100% GTO range, using it in pontual situations may lead to wrong conclusions. Ex. GTO plays 30/20 and you play 25/18, GTO is likely to have more T9, 98, 87 in range than you, thus having a different perceived range.

GTO vs GTO is a break even. Villain is not GTO. GTO can mix your check/raise expecting V's GTO to have 88, 99, TT, KK in range (as well as bluffs), but without extensive information on villain, you won't be able to configure your GTO to know how V's GTO should act. Is possible that if you run GTO as if you were the villain, against you, it could call with A high, as it is also a way to reduce exploitability.

The above are my uninformed interpretations of GTO.
My personal oppinion regarding GTO is that it is useful, but I think in micros it has potential to be deceiving, unless you can configure the situations with more information than one should ever have on micros (tens to hundred of thousands of hands on each villain).
If you are having good results playing GTO, my advice would be to keep playing GTO, as when you progress further it is more important and you may now be saving adaptation time form the future. But for me, there's a lot of concepts to consolidate before GTO starts to be a necessity.

When I told you to review your story, I meant "as if you were villain". What hands would you fold to the story you were telling.

Interestingly, the solver would bet all QJ with Qh in this spot and check all others on the river. I'm not yet able to really fully wrap my head around this:

My hint is that Q♥ would block more suited combos of Qx (KQ, QJ, QT, ...), but I may be very wrong.

I'm not to familiar with GTO, but in general I would play straightforward on NL2. Check/raise bluffs aren't working that well against a unknown on NL2 I think. Now you isolate yourself against top pair or better on the flop and that makes bluffing on the turn even harder. Offcourse the king could be a scare card for the villain in this hand.

Cheers,
SDK1987