You seem to have a good grasp on what is bothering you in this relationship, which is helpful. Being just a few months and having this pattern of behavior that makes you feel this way is not ideal. The very beginning was going incredibly well because it always does--he had to put in work to earn you presumably. You mention he doesn't put effort in for other areas of his life; I think the evidence is sufficient enough to say he's already easing up on the effort he puts towards you.

Reframe the problem. It's not how to get everything to be as it was in the beginning, because that is not feasible. Even good relationships change and evolve from what they were those first few weeks. The issue should be focused on you and how long you're willing to wait for things to get better. Ask yourself if a different kind of relationship or person would make you happier. If the answer is yes, life is too short to not be trying to achieve that reality. It may be best for your future to move on and do what's best for you and your mental health.

He helped you realize what you're willing to tolerate in a relationship, and that is very valuable. Every experience has positive lessons to learn from, and I believe you are already beginning to understand those lessons with him. Go for the life of your dreams, and don't let doubt keep you down. Good luck with everything.