Hey mate and welcome to the cash tables.
First off, what I would suggest for you is to play a lot tighter pre flop. When you play stronger hands pre flop you will find that your decisions are a lot of the time easier post flop.
In the first hand we need to be folding AT when the BB shoves, especially when we have no information telling us that the BB is a crazy player. My advice would be, before you call you should think to yourself, "would this player shove with a hand worse than mine" like A9 or K7, If you think that they wouldn't then you should fold, you will learn quickly that only the worst players or players who have lost their mind will just shove pre flop with hands as bad as those.
In the second hand we should be folding KJ from UTG and definitely folding to the raise, remember that position is very important in poker and when you are UTG you are in the worst position that doesn't have to put money in the pot. So don't put money into the pot that you don't need to from this position.
Simply playing less hands out of position will improve your game instantly.
When the flop hits and you see the monotone board I understand why you would get excited, that looks like a good flop for you. When you bet here you need to know why your betting. Ask yourself "why am I betting this", is it to get your opponent to fold a better hand? Or is it to get your opponent to call with a worse hand? On this flop, If you think that your opponent will fold say 99 or maybe QT then yeah your bet is a bluff, if not then do you think that your opponent will call with the Jack of spades and no pair? then your bet is for value. If neither of these things are true then why bet?
When the turn completes the flush draw, we need to think about what to do now, we need to think about how likely it is that villain will call a bet with only a pair and no flush, the likelihood that our opponent will call this bet will usually be proportional to the amount we bet at the pot, eg. villain will call a smaller bet with worse hands and call larger bets with better hands. Considering that a pair and no flush here is a very weak hand we would need to bet very small in order to get villain to call.
Now lets think about if villain does have a flush, so the first thing we think is that there is only one card in the deck that beats us. Which is true, and it is also true that villain will definitely call us if they hold that one card when we go all in. What is more difficult is thinking about if villain will call us with a worse flush, remember why we are betting - is it for value, or as a bluff? In this case we are definitely betting for value, which means we need villain to call us with worse, and remember that by betting the largest amount we can, we would expect villain to only call us with a very good hand. So lets think about what hands play this way that get to this turn that call our bet that we beat.
The next best hand that is worse than ours is any hand that has the Jack of spades in it, so we need to construct the hand from the beginning, making sure that villain would play the hand the way they have with the Jack. So what hands will raise us pre flop with the Jack? I think maybe AJ, definitely JJ, what about KJ? or QJ? would they raise pre flop or just call? IMO probably just call so we can remove those hands from villains likely holdings. So now we need to think about the flop, would AJ or JJ just flat call our flop bet? instead of raising or calling?.. Probably would right? So ok that's good, what we do now is we think about the likelihood villain will call a shove with the Jack added to the likelihood that villain will arrive at this spot with the Jack and if those two things combined are more likely than villain having the Ace of spades here then we can shove for value.
The issue is there are really only two hands that get here that contain the Jack of spades. When we look at what hands get here that have Ace of spades it doesn't look good for us; AK AQ AJ AT maybe, AA might raise the flop so maybe not that, but that alone is a lot more hands than just AJ and JJ. And since we know that villain is definitely calling us with all of those hands we might say that villain will call more often with the Ace of spades than the Jack of spades just because villain actually HAS the Ace of spades more often. In order to swing it the other way we need to add more hands that villain will call our shove with, the Ten of spades and the Nine of spades etc, but remember the strength of our opponents hand when they call is usually proportional to our bet size, so the lower their flush the less likely they should be to call our big bet.
You know how to avoid having to do all this work? Just fold KJo from UTG