How far can I go without intensively studying theory?

For context, I’m 1800 chess.com and I know 3 openings. The Halloween gambit for white, and the Sicilian dragon and alekhine for black. Within these openings I feel comfortable enough, but most of my matches end up with opponent’s gaining a lead out of the opening due to my lack of understanding in different opening positions. I really don’t want to study theory and was wondering at what level does it become impossible to progress without hitting the books.