The natural place for the bed in this room is the wall opposite your bathroom, with the windows to your left, the entrance door to your right, and the barn door behind you on the right. If you have a dresser, it can go on the wall by the entrance door or on the wall where the black triangle is now (provided you still have 3' of walking space between it and the foot of your bed).

I would place the bed in the middle of the wall opposite the bathroom and barn door.

By vents, do you means the heat and a/c vents? Google “heat register deflector” to see various options to redirect the air flow away from you.