I've got some ideas for the corners and ceiling that I'm reasonably comfortable with, but for the side walls, there's no clear solution that's jumping out to me. I spent the last weekend DIYing 6 frames that are 80cm x 120cm x 11cm, and want a 10cm air gap behind them.
Ideally, the solution would:
Not involve too much work (e.g. mounting four brackets per panel * six panels * four screws per bracket = nearly a hundred screws, which seems a bit tedious for a non-carpenter like me)
Not be too unsightly (you'll see the side profile upon entering the room)
Allow for