I have a 2013 Mac Pro Trashcan with a spiders web of cabling to all of the devices I've got connected to it.You'd expect it to be thicker because of the expected mini-LED screen and cooling solution, not quite so sure about an expansion possibilities beyond expecting 4 Thunderbolt ports.
Please! I want a internal storage in an iMac system. I'm not interested in a massive 2019 Mac Pro.