I wish I had your dilemma. My only suggestion is that you budget $500 - $1K for acoustic treatment of your space. You basically are living in a giant echo chamber, and no matter what you install, you are going to have issues with echoes/standing waves, reverb, etc.
There are lots of good choices out there. I would start with some acoustic panels and/or wall hangings made with acoustic absorbing material (not just foam). Good luck.
There are lots of good choices out there. I would start with some acoustic panels and/or wall hangings made with acoustic absorbing material (not just foam). Good luck.