Does a big nose and dorsal hump cause issues with seeing the blurred outline of your nose in your vision?

A large nose should not impact your vision in any significant way. Best of luck if you decide ot have a rhinoplasty.

Like any other object in your field of view, a large nose can definitely be more visible to you than a smaller one. This is almost certainly not a vision issue, so it would likely improve to some degree after rhinoplasty.

Everybody can see their own nose. You may be more aware of this if you have a larger nose. If you have a procedure to decrease the size of your nose you will still see it but may be less aware of it. There is no visual problem with a larger nose except that it can block your vision a little looking down and inward.