u/Beginning-Zombie-637

I'm a player who started with e4. Then, I switched to d4 after learning the Queen's Gambit for white and Benko Gambit for black. I'm finding d4 a little slow and I'm mostly stumped in the middlegame. I find e4 ideas easier as they have more tactics. The only thing is, there are so many replies that black can play for. So, how do I make this switch? Should I learn the theory for each opening like Caro, Sicilian, Scandi and so on? Or is there an offbeat line that can counter all of black's lines?

I'm 1500 rated on chess.com. Any suggestions?