Hi guys! this is actually my first time posting in the forum so I apologize if I'm posting in the wrong place. I'm a new player and still trying to learn the game and would really appreciate your opinion on this hand I played in a 9 man sng. So I'm the BTN with 1644 chips just waiting to double up, the blinds are 25/50 and get dealt KQd. Preflop goes like this:
UTG: folds
MP: calls 50
CO: folds
BTN(me): calls 50
SB: calls 25
BB: checks
I wanted to make a comment here and say I didn't bet here because the past 2 rounds I bet 3-2.5 times on the BTN and since i have KQ suited I was kind of afraid someone would 3bet me putting me in a tougher position and I belive this is a hand that plays very well post flop. I also wanted to hide my hands strength.
*** FLOP ***
[6d 4d 7c]
SB: checks
BB: checks
MP: bets 300
BTN(me): calls 300
SB: folds
BB: folds
So the flop comes and gives me a flush draw and the MP decides to bet 300 with the pot being 236. With his betting size I assume he either has a set, a straight that he's trying to defend because of the flush draw or he's just bluffing. I decide to call and see the next card.
*** TURN ***
[6d 4d 7c] [2d]
On the turn a 2d comes and gives me a king high flush, my opponent checks and I check back because in my head he's showing weakness and if I bet he runs away and I want to give him a chance to bluff the river since I believe that with a check I represent a missed straight draw and I think it's very unlikely he has me beat here.
*** RIVER ***
[6d 4d 7c 2d] [Tc]
On the river comes a Ten of clubs doesn't really change anything and my opponent decides to bet pot size. At this point I think to myself if he had the flush ace high he wouldn't be betting as big since he has the nuts and wouldn't want me to run away and I believe most of the time I have him beat
since the only hand that beats me is the Axd, so I decide to all in him to get as much as I can out of him and I know he won't fold a set or a straight since the difference is only of 438 chips. He calls. We both show our hands:
Me: shows [Kd Qd] (a flush, King high)
MP: shows [5d Ad] (a flush, Ace high)
So my opponent ends up having the nut flush and I'm eliminated of the sng and out of the money. That's how the hand went and my thought process please let me know if you guys think i misplayed or my thought process is wrong I'm really eager to learn and would love the opinion of how this hand should've been played. Thank you and I apologize if I was a big fish here hahaha still learning.

Raise pre with an increased raise size to account for the limpers. Players in the micro stakes sngs are limping very wide so raise to punish them. The mid blind stage is also when we want to start stealing and a raise here will sometimes illicit folds. The risk of a 3bet is not a reason to limp behind as opposed to raising.
Otf villain has TPTK, low overpairs or worse fds in their range as well as the top part you noted [sets]. Flop call is good particularly as you have two overcards to the board which may be outs. I'm betting ott for value. Villain is likely to be a poor player [limp calling pre] and isn't getting away from the part of their range that you beat. We also want to set up a river shove which is easier with a turn bet. Generally in the high blind stage of an sng we want to play strong hands fast.
River shove is good. You got coolered. Don't be results orientated.

Hi man, good that you're trying to learn. I can definitely give you some pointers as well. Don't let my post count fool you, my older account is banned.

Make sure whenever you make a post like this to post the buy-in level so other members have an idea about the strength of the player pool you're playing against. Also add how you perceive villain to play, such as passive (lots of limping and check/calling), overaggressive (a player that fires away in every pot he plays), etc.

As for this hand:

Preflop:
Raise to 3.5x or somewhere in that neighborhood. Villain limps in what is presumably a low buy-in game, which means 99% of the time he's a recreational player. Your range is stronger, you can isolate the recreational player and you're in position. Your hand plays fine against a 3bet anyway, so that's not really an issue either and at a lower buy-in level there won't be a lot of 3betting anyway. You also mentioned you played your last three buttons, which is actually a good thing here because it make your perceived range weaker than your actual hand is. There's really no reason to do anything else here and it's actually the type of situation that you would want to wake up for in the morning as a poker player.

Flop:
Villain is probably a recreational that isn't a very thinking player, so I wouldn't narrow his range down to straights, sets or air based on his sizing. For one, only absolute tilt monkeys overbet a coordinated (read: drawheavy) board here with air against three other players, so I would exclude complete airball bluffs. Villain probably bets a strong 7, some small overpairs, strong draws or occasionally a set with this sizing, even though it's bad. When he bets 300 there's 526 chips in the pot and you have 1594 behind. Shoving can't be bad based on the money that's already in the pot and the equity you have against villains perceived range. Calling is okay as well. I would probably shove as villain likely pushes you off of your equity on the turn when it's not a K, Q or diamond. Based on his flop sizing the chance that he pots or overbets blanc turns is high from my experience and then you can't really call. Folding two overcards and the 2nd nut flush draw is a lot of equity being denied by a range that consists of some hands that we're a small favorite against on the flop, like the 7x hands and small overpairs. Sometimes it's best to just look at what's already out there and make your decision based on the fact that there's over 30% worth your stack in the pot. Would be player dependent and stakes dependent for me though, wouldn't take this route if I believe I have a huge edge in the field I'm playing against.

Turn: Just bet small to keep him in the pot with his pairs + weak diamond draws. It's presumably a lower buy-in level so you just want to bet your valuehands. You can suck him in with a smaller bet to make sure he calls with the range we described. You probably don't need to be very balanced against this specific player. Size up the river shove, which can be done with a smaller bet on the turn as well, and jam river.

River: Totally fine man, just an annoying cooler. Those happen sometimes, don't let it bother you.

Happy holidays!