Equipment racks can be made to slide in and out plus rotated for service. MidAtlantic is the most well-known and they have the hardware kits to do so. It's just a baseplate that the rack is bolted to, that is on tracks, allowing it to be moved out into the room and rotated.
Here you go:
https://www.legrandav.com/products/racks/slide_out/srsr_slide_out_rotating_rack_system
I'd suggest contacting a local A/V integration company to assist with this to ensure you get all the necessary parts, plus consider adequate cooling, electrical, framing, etc.