I know I’m not struggling, yet I constantly feel that way
It’s strange
I would say you are struggling and it's both real and ok. (I mean in an empowering way not insulting, in case it doesn't come across). Allow yourself to experience that and don't lie to yourself that everything is fine and that you SHOULD should feel another way. If you feel sad, disappointed, frustrated those are all real feelings and it's normal and healthy to feel them sometimes .
As aspies we all struggle to fit into a world designed around NTs. That's one big struggle by itself and it also sounds like you are struggling with self esteem issues. I am as well btw. I've put a LOT of work into it and still struggle, but it's so much better now.
"I been asking myself this question: how can I do better? While there are some answers, there isn’t a definitive one" I think it might be better to try to rephrase this question and look at it from another side, "how can I feel better about what I have achieved" or "what can I do to make myself FEEL more successful"
Try making a list of a lot of things you have already accomplished and then think about all the big and little hurdles that you overcame that an NT didn't. Just by getting to work or school you probably had sensory issues and social issues you had to deal with and that's before you even did any work. I'm sure the list of both your accomplishments and all the struggles you have overcome is larger then you tell yourself.
For me doing better in the NT world just involved masking, hiding my struggles, burning out and still feeling like I wasn't successful because I knew inside it wasn't me, it was a character I was playing.
When I revaluated I realized I didn't even want the status symbols I was judging myself for not having. And I also realized I'm not money motivated, having more then is required doesn't make me happy. I was struggling to work stressful jobs I didn't like, fighting for promotions I didn't actually want in order to buy stuff I only thought I was expected to have. What I actually wanted and what actually made me feel successful was a less stressful life that allowed me the time for my special interests. Now when I compare myself to others I can see that I have more free time and less stress, looking at it that way I'm better then most of them.