Im alittle bit nervous now when reading about the problem of pci-e cards issue of ryzen. I building right now a similar pc for music production. My cpu will arrive in some days now and its the same cpu 3950x as you have Jouleskeys. My mobo is a gigabyte x570 auros master. The thing is that i have a thunderbolt pci-e card wich i need to connect my soundcard (apollo x6) to. And also i have 2 pci-e card uad2 solos wich i want to use.
I hope there will not be problem to get these to work. My first time with amd now and that make me a little bit nervous to hear your issue about pci-e card