First. Beautiful system and room.
If it was my system I would work on improving the venue. I am sure it can be done tastefully with acoustic panels and large throw rugs. Sorry to keep asking for more, but views of all angles of the whole room would be helpful. But before I invested in bigger speaker and or more subwoofers I would see how much improvement you can get.
Often if the room is not dampened enough then you end up turning up the volume to reach a satisfying level. With high ceilings and an undampened room you could end up overloading it.
Also, given the other equipment I'd probably improve the streamer first. But, not the question you asked.
I hope this is helpful.