I’m finding it hard to eat 6 small meals a day

I’m fit but looking to build a significant amount of muscle mass. I don’t eat enough, I’m always at a calorie deficit. I meal prepped so that I can ensure that I am eating more. The plan is to eat 6 meals, 3 hours apart. I’m having a hard time because I’m not hungry within the 3 hour time frame. Is eating a lot the only one that I can possibly build?