I am pretty new to tournaments, so my logic is probably ****. Please pick it apart at any decision point. Thanks

25 bb deep halfway through a low stakes bounty tournament. My bounty is half the buy-in. Folds to hero in CO with Ac5d.

Raise to 2bb, SB calls (60 bb), BB calls (30 bb, 1/4 buy-in bounty).
I had absolutely no idea what to make of SB's flatting range. I thought it could include a good amount of strong hands, trying to induce shoves from BB, but I was not sure.

(6 bb pot) Flop comes AsQhJh, checks around.
I checked for pot control and to avoid x/r. I don't really want to call any x/r at this stack depth. And I was still weary of SB who I thought could have hands as strong as QQ.

(6 bb pot) Turn is 10d, checks to hero who bets 3 bb, SB calls, BB raises to 10, hero folds.
What worse hands are calling my bet here? All flush draws because my straights and sets/2p are paying them off on the river. My range is also protected with lots of Kx that checks flop, so in theory I shouldn't face many raises. Maybe theres still not enough worse hands that call.

The fold I'm sure is standard with a weak hand like I had. I thought I wasn't deep enough to just call. Thought about turning it into a bluff bc my range has lots of Kx and theirs shouldn't. But in the end there is not enough fold equity due to my bounty.

Looks fine to me on each street.

I'm not sure how you can say the BB's range "shouldn't" have Kx given that he's calling to close the action in a multiway pot. In any case, that range changes when he check-raises the turn, and I don't see any reason to think he's bluffing.

I didn't think much of his Kx would check the turn because I have a lot of hands that are pure give ups and are checking behind.

Ah, got it. Maybe he suspects you have a one pair hand and he can get another bet from you that way. Or it's a low stakes tournament and he's only thinking about how good it will feel to get one extra bet by check raising.

In any case I don't think there's reason to think he's bluffing: Either he's thinking "I have the nuts," or if he's good enough to be a thinking player, (which you need him to be to be check-raising here without Kx), then you probably have Kx too often to make a bluff profitable-- I don't know if he would think that but it's certainly a reasonable thing to think.