You got the money in with 80% equity. Majority of the time this is going to work out for you. I wouldn’t consider it high variance bc you called with a suited connector preflop and flopped the flush, as you pointed out it’s really hard for him to have a flush and if he somehow does it’s kind of just a cooler. You could raise his bet on the flop and if he 3 bets consider him to have a higher flush and fold if you are worried about finding out where you are at. Other than that you got the money in good and unfortunately it didn’t work this time. 5h6h is a profitable call the deeper stacks get. I’m not sure if it is profitable to call preflop when the raise is so substantial bc you are going to be playing an inflated pot with a drawing hand and depending on the player that raise could narrow his range to premiums. Depends a bit on your read of the table and if you think you will get called down on a made hand