Gigabyte X299 Ultra Gaming Pro almost there, still some issues

Hey !

I wanted to update editing station from Mojave to Catalina and from Clover to Opencore and I have a workable computer but there is still some issues. Here is my config :

MotherBoard : Gigabyte Aorus Ultra Gaming Pro (Bios F4h)

CPU : Intel i9-7920X

GPU 1 : Sapphire RX Vega 56

GPU 2 : Sapphire 5700XT

RAM : 4x 16Gb Corsair 3200 Mhz

SSD : QVO 2Tb

Wifi : Broadcom brcm43xx

My main issue is the wifi, I have very slow speed (around 2Mbps with speedtest) and I don't know why. My second issue is that sometimes I have the "startimage fail" issue. I read it can be DevirtualiseMmio but it is already True in my config..

You can find my EFI folder here : https://www.swisstransfer.com/d/67c7881e-cc68-4b41-a81c-5a5be1e52e5a

Thank you for your help !