What is the plan for this position? I don't want to just mindlessly develop.
It's a little late for that, lol. This looks like a london vs hippo. If you wanted to develop with something in mind that needed to happen many moves before this position.
As far as the plan... not all positions have a long term plan. This is like a Carlsbad structure but with a pawn on d6... meaning white doesn't have the normal kingside ideas after putting a knight on e5... black has plans though. Black can go for a minority attack or the e5 pawn break... but white has nothing long term, and can only keep pieces active and wait for the character of the position to change before forming any long term ideas.
My opponent played moves just to make them and ended up winning. I feel like he was waiting for me to self-destruct.
Yeah, that's probably a good way to win this position a lot of the time against inexperienced players.
The way I think of it is, you have to play the short term game. Just try to stay active from one move to the next, and keep the position a draw... you can turn your killer instinct on later in the game after something happens, probably in the late mid game to endgame... mostly this position requires patience. Like I said, not all positions have a long term plan.
I got into this position as white in a game recently. I felt very lost in this position and spent a lost of time thinking how to proceed. What is the plan for this position? I don't want to just mindlessly develop. My opponent played moves just to make them and ended up winning. I feel like he was waiting for me to self-destruct.