Hey! So, I don't have much dysphoria either.
My advice would be to wear larger shirts, a sports bra (I personally don't agree with wearing binders because it can make you feel less dysphoric but it will harm your body in other way, so Î personally don't use them, I rather sports bra) and, about the shirts, I guess you should avoid white shirts because it will make your chest more noticeable, try to wear shirts with a darker color or shirts with patterns. I hope this helps you and (I know it's hard af!) but try to ignore what others may think or say to you because what matters it's how you feel inside and how you see yourself. I can give my own example; I have a face with soft edges, long hair and wide hips so, of course, I don't pass, even though I'd love to pass, but the most important thing is that I see myself as a boy, I feel like a boy and I think like a boy, it still is frustrating and disappointing the fact that others don't see me the way I see myself but this is the only thing I can do before starting any treatment at all.

So, I'd recommend you to wear a sports bra, larger and darker or patterned shirts (you can wear vivid colors too, as long as it's not white and it's larger, I guess it will make your chest less noticeable, but before top surgery, unfortunately, these are the only things we can do).

Note: you could wear a men's perfume to feel more masculine too.