On the 3rd try with a new iso, and on the media test on my new Ryzen
computer, plymouth started for a little while, and then aborted, but
with all the same errors as before.

So I decided to reboot and just click install and see what would happen.  

( I used the latest Everything Boot Rawhide iso )  

I now have a working Ryzen computer with Fedora Rawhide.     

https://www.dropbox.com/s/r16ed7epmzv72zj/ASUS_X570_Ryzen3_1200AF.jpg?dl=0 

This is an ASUS motherboard with no wi-fi ( I have a wi-fi card to install later ).    The
video card is a used Power Color 5500XT ( bought in USA for around $ 129 USD plus tax )
Rawhide is on the primary NVMe drive.    Cooler is the massive Noctua.

I purchased the Ryzen 3 1200AF from 

        aaawave.com 

for around $ 77.95 USD ( free shipping ).   No problems.

I spent a lot of money on the motherboard, having purchased it before the X550's were available.
I am not pleased with the PCH fan-speed, but it is only 1600 to 2150 at idle in BIOS.    That is with
the PCH fan being new.    Imagine what it will be like in a year or two.   Ouch !

To be continued.

David Locklear