The question is passing as what. As someone else? How about passing as yourself which is a lovely idea.
Are you authentic or inauthentic? If you are transgender I suggest the former I true. Which then begs the question who are you trying to pass as?
My confidence has soared ever since I have understood and ingested the fact that I am transgender. Hence when I go out I am dressing and not crossdressing (which is a term I have increasing disdain for). No matter what clothing you wear you are still you.
Yes I know, many of us don’t desire to be recognized because we have built lives that we think (rightly or wrongly) depend on us not being discovered. That is all well and good and, as out as I am, I still don’t advertise to everyone that I am trans. However if it gets out then so what of it. It is a key part of my identity and I am not ashamed of it.
Heck there are transitioned people who don't pass. There are even cisgendered people who regularly have their gender questioned. Are they any less authentic for it?
So you will likely stop thinking about passing when you finally arrive at a holistic and complete view of who you are.
Now you are really passing.