So I always hear people saying 'your too shallow to play 67s here' which is obviously true in certain spots due to the implied odds of straights and flushes. There comes a certain depth though where the value of suited aces drastically goes up due to the ability to make flush over flush.

I was just wondering at what stack depth low-medium suited connectors are at their peak EV both in a standard game and also in an aggressive game that's playing larger? I know they are important to play for range balance and board coverage but in a vacuum (ie. not thinking about balance just purely playing a hand in isolation) what is the perfect stack depth? Is there a certain depth where they become -EV (presuming no player skill edge) or is the threat of flush over flush never significant enough to make them -EV?

For HU I have an exact answer- in position the EV of 76s in SB goes up as stacksize increases from 5 to 25 (and presumably also increases for higher depths, but tails off to a limit).

OOP it decreases until 6bb (where it can no longer call open shove), and increases from there until around 18-20bb (where you 3bet shove/iso shove it less). From then on presumably it will keep increasing. Suited connectors along with being very playable postflop, is also playable preflop (very good to put into shoving range in all positions).

Also an increase in value of suited aces doesn't mean that ev of 76s goes down as well. The EV of AA for example increases value as stack depth at the fastest rate of all hands. What's true tho is that the ev of hands like A2o Q6o go down as stacks increase tremendously.