I would demo the closet and use an infrared repeater system to get the av rack outside the room.
I would extend the riser outside the room and match it's height with the first step. I would add an island
style riser on top of the riser if need be, to create proper sightlines for the second row.
I would deepen the front AT space to 30" and frame the upper side wall flush with the lower wall and use this
wall depth for window plugs.
And I would take to heart, Shawn's message about 10 pounds of stuff in a five pound bag.
Is that a minisplit between the windows? And how tall is the room?