This tutorial for installing macOS Catalina using OpenCore has been adapted for Proxmox from Kholia’s OSX-KVM project and Leoyzen’s OpenCore configuration for KVM. You can get the full sourcecode on my GitHub here.

If you’d like to use Clover instead, use my older tutorial, but OpenCore works better!

Source: Installing macOS Catalina 10.15 on Proxmox 6.1 or 6.2 using OpenCore – Nicholas Sherlock