Rarely did I put mixers and synths on my bench. Unless the mixer is the size of a rack toy. Once in a while I might stand one on end and lean it on my riser, but mostly I use my cart.
I have something like this:
Easy-Up Four Wheel All Purpose Service Cart | EZ45G | Easy-Up
Easy enough to make your own. I have carpet on top to help prevent scratching things. It sits in the middle of the shop. I do most work on it, leaving the bench for chassis or boards. I sit a combo, like Fender twin reverb, up there, makes taking the chassis out easy at eye level, then swing around and put chassis on bench, leaving cab on cart. But keyboards sit on this quite well, and I can spin the whole thing around to get to back or front easily. It is on wheels. With the carpet, I can lay a synth on its face, won't hurt the keys.
But a big mixer shines there. With 200 knobs, the weight on any one is tiny, so you can lay them on their face for disassembly. I work on them from the front largely, but to check them out, I spin them around and run from the rear. SO I can plug signals into any jack simply, and then reach down and work the sliders and controls. No way a 48 channel mixer fits on my bench.
I got a long scope probe to reach from my bench riser to the cart, but if I need to scope a lot, I can pull my scope off the shelf, sit it on the floor next to me facing up next to my knee, and scope in the mixer.