So after a couple attempts to get Catalina working on my 5,1 Mac Pro, I finally got it to work by installing straight to a drive. The External boot drive setup did not work. The problem I now have is that I have dual monitors running on my Nitro+ RX580 and only the DVI output is working. The other monitor is using Display Port. I've had zero issues with Mojave using this setup. Now even in Mojave I get only the DVI monitor. Was it the disable SIP step in the process that caused this? This issue started after doing that in the process to get Catalina to install. I've since tried to enable SIP but still only one monitor.