It's easier and more successful to use non matching cards when using more than one Gfx card for passthrough. AMD Gfx cards have had more issues lately but the newest 6.8rc's have the patch to fix the problem now.
Can't help you with so little info, post your current vm xml, screenshot of your vm template, syslinux config, Tools>System Devices & Tools>Diagnostics.
If you wanted to start fresh you could stop docker service and delete docker image. Start docker service which will then create a new fresh docker image. Goto Apps - Previous Apps and install your apps fresh which will retain all your settings and info from your Appdata. Then you have a fresh clean docker image.
No drivers to install in Unraid. Problem may have to do with it having dual alike audio onboard(first time seeing a board with dual audio onboard). Tools>System Devices what is iommu group(s) for the onboard audio?