Well, the opening you play should fit your playstyle. Like the Queen's Gambit is a solid opening. And you can play something like Pirc defense if you don't want to memorize any theory. It is really straight forward gameplay.
But opening theory is good to learn, also the ideas behind the moves. You can't really tell if you should push you pawns or take. And it really depends on your play style. If you are aggressive, close the center and start an attack. If you are passive, play solid and try to break through later on.
These are all just my own opinion.
For some reason, I can't apply to the openings the same attention I apply to the other phases of the game.
During midgame, I really enjoy defining goals and a strategy, searching for the best moves and asking myself how my opponent might respond.
The same doesn't happen during the opening phase. I can apply a bit the basic opening theory (develop, control the center, keep the king safe, etc.), but I get confused easily, especially about pawn usage. Understanding when to capture, move forward, or do nothing is really tough for me.
I don't want to memorize openings as a solution. Instead, I would like to understand how to improve my reasoning and calculation skills during this game phase.
Do you have any recommendations? Thanks in advance!