I relate so much to your plight!! Being confident is genuinely so difficult, but everyday is a chance to practice.
Something I do? Play pretend.
Listening to music that pumps me up and wearing an outfit I like usually helps, but the rest is all an elaborate disguise. At first I thought it was delusional for me to think I’m hot shit, and it felt silly to even pretend like it was true. Recently, I’ve actually started to believe it, and I think normalizing that thought in my head through pretending really helped.