I’m having trouble figuring out what your setup looks like from the photos. From the first photo, it looks like there is nothing but a wall to the right of the TV. I can’t make anything out from your second photo, as I think there is glare off the TV.
Do you mean that you want to put 3-7 amps behind your TV in that same space? If so, I wouldn’t do that. Find another location in the house. If you have to use this space, then I might try and use the cabinet below, or behind the decorations at the top...well vented of course.
Thanks and will try to clarify . . . the TV is on a mount and extends about 22” away from the wall so there is space behind the TV to effectively hide other components (cable box, Apple TV, etc). I am intending to put a set of shelves to the right of the TV mount where it is attached to the wall to hold anywhere from 3 to 7 Sonos Amps that are currently scattered about the house in random areas. Hope that helps
Getting a custom shelf unit built might be your best bet. Doesn’t have to be fancy, I made some using racks like these (below) cut to width and the support wires inserted into holes drilled into nice oak 1x2 boards. You can get the exact width and shelf spacing you want. Just buy the depth shelf you want.
https://smile.amazon.com/Lonian-Cupboard-Organiser-Cabinets-Counter-Tops/dp/B08CRHZPWC/ref=sr_1_58?