Burn in’s a myth, the closest thing to it would be your brain adjusting to a new sound signature.

Perhaps you just prefer the sound of your older headphones more? If you try the Fidelios for a bit more and still prefer your old ones, there’s no harm in returning the Fidelios and sticking with your old pair, or trying other headphones if you’re still set on getting something new. It’s not like just because something is newer and/or more expensive, it’ll automatically sound “better” to your ears.

Picked up an SR-Lambda Pro and 006t to run it pretty recently, and I’ve already fallen in love with them

Aesthetically, I’m partial to bead blasted aluminum and carbon fiber finishes, with maybe some darker wood accents in the occasional spot.

I’m not a particularly big fan of leather and glass personally, nor do I like glossy plastics. Matte plastics are fine though. Functionally though, wood would probably be pretty easy to work with without requiring specialized tools and or skills.