I have Magnepans and my front wall (wall behind the speakers) has combo absorption/diffusion panels from GIK. My rear wall has two absorption panels on stands behind my head to block a window with some more combo absorption/diffusion panels on either side.
So far, I’m happy with how it’s turned out but I’m not an expert by any means. It looks cool, so at least there’s that.
From what my research indicates you really want to have thick panels to absorb as much bass as you can (and it still won’t be too far below 100k because of physics). Those bass traps you see, whether they are the triangle ones in the corners or the thicker panels generally also absorb mid and high frequencies so you want to use the thickest you can get so you don’t end up with the need for more bass absorption after you’ve already deadened the room with thinner panels and run out of wall space. That’s why diffusers are popular so you don’t over dampen the room.
I would suggest looking at the Acoustic Insider YouTube channel. He seems to know what he’s doing and he doesn’t obviously seem to be selling anything.
I have pictures of my setup in the last post in the GIK circle if you are interested in seeing it.