My mini-ITX work desktop has no problems with a 5900x and a Radeon VII pro running Rocm work, using only a tiny heatsink on the 5900x (and some high-airflow fans, but nothing too incredibly loud). It doesn't thermal throttle, but tops out around 80-90 degrees C.
The 7000-series seems to be a different story: you really need a big cooler for those chips.
I have the same CPU + GPU combination, but used on an ATX MB with a Noctua cooler with a double 120-mm fan.
While the larger case and cooler makes the cooling easier, the fans are normally inaudible and the CPU stays under 45 Celsius degrees when not doing heavy work, and the temperature may raise up to a little over 60 degrees Celsius when 100% busy.
From what I have seen until now, cooling will no longer be so easy for the 7000 series, unless you choose to run them in the Eco mode.
The 7000-series seems to be a different story: you really need a big cooler for those chips.