Having a rough time at the $100 6max tables on UB lately, and I'm trying to find out what part is due to bad play and what part to bad luck.
I used to do very well in those games - then I moved to the $200 tables, quickly lost the 10buyins i had set apart for those (where 6 of those were probably unavoidable, like flush over flush things and the other 4 were probably avoidable, like flopping overpairs against sets).

Anyway, back at the $100s I'm having an extremely hard time to keep afloat. Past 10k hands I'm not down a shocking amount - about 7 buyins, but what worries me most is the fact that I don't seem to be able to pull any successful move.
I'll post a few hands below, but as far as I can see the main culprits are as follows:

1) by far the biggest losers: AA, KK. Especially in reraised pots I have a hard time getting away from those on innocent looking flops, especially against hyperaggressive opponents.

2) whereas it used to be that raising pf and cbetting would be at least sufficient to keep up with the blinds, now I'm hardly ever taking down a pot without a struggle. Some players in the game 3bet me virtually every time, and others simply float any flop. I checked my 350 hand session for today, and only 12% of cbets was successful. In about 50% of cases I was checkraised, the other cases floated.

3) Not able to produce hands with enough showdown value. For example, the last 3k hands I have made 8 sets (statistics experts, is this indeed not enough or is it my imagination) out of which only 2 resulted in a decent sized pot won. 3 resulted in stack loss (2 overset, one outdrawn) and the other 3 nobody had anything.
Other than that, I simply have too many sessions where I can't get anything better than middle pair, and with the aggression levels at these games I'm often hesitant to invest half a stack with those. In short, I'm losing almost everything which goes to showdown.

4) Problems with shortstacks. Maybe I'm not combatting those in the optimal way, but it seems that they just take my stack 30bb at a time. Losing most allin preflop confrontations, and simply can't show down a winner against them.

5) Unsuccessful bluffs. I don't bluff a lot in these games, but there are a lot of people getting out of line, 3betting preflop with crap, 3barreling garbage hands or simply bullying too much. It used to be the case that at least once every 100 hands or so I'd rake in a medium sized pot with a well-timed bluff, but those days seem to be over. Since I'm getting pretty weak cards I've tightened up considerably (down from laggy32% or so to 20%), but it does not result in people giving you more credit when you come in for a raise, even from EP.
Anyway, this is doubly troublesome; I'm not making good enough hands to bet anything for value, and most of the time I have at best a pure bluffcatcher. So, I need the occasional bluff to work in order to make up for all missed flops and small pots lost.

Some hands as a sanity check:

1a) As said, big pairs in reraised pots:
I have [Kc] in the BB, CO raises, I repop to $11. CO calls (both started with full stack). I haven't been 3betting a lot.
Flop: [7s][8c]. I lead for $20, CO pushes, I call?

1b) [Ah] UTG. I raise to $3,50, CO reraises to $16 (he's been doing every other time I raise). Folded to me, I call. (Thought of reraising here, but I'm pretty sure he'll fire a pot bet on any flop). Flop: [2h][6d]. I check, CO bets $30, I CRAI?

2) Very standard situation. I get [Jc] on the button and raise one limper to $4,50.
BB calls. Flop is [Th][Qs]. BB checks, I make a $8 Cbet, BB checkraises to $20. This is the fate of most of my Cbets. How many times does this have to happen before you play back?

3) Pay off this river? I get [Jh] on the button. I raise to $3,50, BB calls. Flop is [6h][Ts]. BB leads for $5, I raise to $18, BB calls. Turn: . BB leads for $12. I call?? River: . BB leads for $30?

4) I have AQo in the CO. Button is short with $30. I raise, button calls, rest folds. Flop: 45Q rainbow. I bet $7, button pushes, I call?

5a) I don't like to 3barrel a lot ( in fact I hardly ever do it, and if opponent would pay any attention would know this). Here my hand improved on the turn, and on the river I didn't see how not to continue firing.
I get [6s] in the CO and openraise to $3,50. SB, BB calls. Flop is [4s][5s]. I fire a $9 CBet/semibluff. BB calls (I'm pretty sure BB would checkraise with a decent hand there). Turn: . Picked up oesd as well. BB checks, I fire $24, BB hesitates but calls again. River: . BB checks again, I fire another $35? BB calls with TT.

5b) I get [9s] OTB. CO raises (he's been insanely loose aggressive preflop) so I decide to repop to $12. CO calls. We both start with about $120. Flop comes [8s][Js], giving me the big draw. CO bets $4, I raise to $25, CO calls. Turn: . CO checks, I bet $40, CO calls again. (Was hoping that the A was a scarecard). River: CO bets $4 again, I shove for almost $40. CO calls with 99?

I can address some of this. You are a 16:1 against being dealt any pocket pair. So 3000x.059= 177. 177x.118= 20.9 (rounded). You should make 20-21 sets on average every 3k hands.

1a and 1b are probably worth an AI.
2. If you are playing LAG style you have to follow up. This can get expensive but here it means RR or CR turn (probably not AI). A lot depends on your read of BB and what you have been doing at the table. I think if you have been getting played back at a lot at a table and you have been folding to it you have to wait for a hand you feel you can play deep or leave and find a different table. LAG style hates to SD a lot. The trick is to convince your opponent you want to SD this particular hand. That gets expensive. It's also why they say you win small pots with AA but lose big ones. If you have a big hand you want to build a pot so if you are going to bluff you have to rep a big hand.
3. I fold that river. I might have RR turn but even a call would have me looking for a cheap SD if river didn't give me trips.
4. Yes.
5a. If you are going to push this I think you need to lean towards going AI on the turn. You have represented strength since the flop but there are now (as you know) many draws so If you had 2p or trips wouldn't you want to charge those draws? Best scenario you have 18 outs (overpair, FD, OESD), still a dog to TT (3:2) but if he plays TT for his stack against that board 'nihan'.
5b. Ideally I'd be AI on the flop but that is a huge overbet. Still it punishes his little $4 blocking bet and you have plenty of outs. You are 53/47 favorite vs AA and only a 57/43 dog vs top set. The turn check followed by the second little blocking bet is what gets me. If this guy wants to play ask him about his stack. If you believe the A is a 'good card' for you then go AI on the turn. If not check behind. This guy has shown no strength. Sooner or later you need to invite him to play. If he calls you you have outs. You were willing to bluff it off on the river with nothing so bluff it off on the turn when there is much more tension for him.

There's an alternative strategy here and that is to just tighten up and play your cards. The problem with TAG style, at least in theory, is since you hit quality cards much less often and they hit the flop even less times you have to be very aggressive when your opportunities arise. As always, the problem of 'timing' (luck) is always present.

I remember a limit hand I had a while back. I had KK and flopped quads on a rainbow board. My one opponent decided he was going to take the pot from me. He capped every street to the river. I think I probably would have laid down AA to him there. He showed A4. It's easy to just pass on the play as 'donk' but there was certainly method to his madness. His timing just stunk. His choosing to do it in a limit game was probably not optimal either. The big bet feature of NLHE makes the method a better option more often. Lousy timing will still stink though.

If I were at a table and continuously losing to hands like the ones you post because my image was so shattered that my bets no longer carried any weight I'd probably look for a different table. This means the only hands I win at that table are those I showdown and lots of showdowns aren't a good thing for any winning NLHE player so I'm probably in the wrong game.

You can run shaite for 50k for sure...but I think cases like that have a LOT of intertwining features causing or prolonging the bad run - playing scared, doing the opposite and getting too agro and blowing out calling hands and losing EV...lots of ways. Have someone else look at your db if you can manage it and get some criticism...get someone to sweat you for an hour...anything!