Radeon RX570 fully working in Mojave but not recognized in Catalina

[Enzo.F]

I'm having a successful Mojave install and the dGPU is working as expected. I use Lilu and WhatEverGreen. Further install wasn't necessary. When I do a clean install on an other hard drive, cloned the Efi and got Catalina running by booting with arg's -x -v -f (safe mode) runs well. But I can't get the Ati Radeon RX570 to work properly.

How can I get it to work as it does in Mojave?

Thanks in advance.

 

[Enzo.F]

Well I did everything as I did on the first fresh install of Catalina and now it's working very smooth according to the first tests. Am watching a 4k youtube (3840x2160@60fps) on monitor 1 and running massive 3d scene in Blender on monitor 2. When switching to the Radeon ProRender for viewport rendering and realtime navigation in my 3d scene, everything is going smooth. Even though I'm on a conventional Sata hard drive over USB. Now I have to clone this working drive onto the SSD inside my machine! Pretty satisfied as for now.

Have to fix audio, that would be easy, have an internet connection but no settings in System Preferences. Bluetooth works out of the box too.