Most Linux users have older machines that are incompatible with newer versions of Windows.
This is so much NOT true. There are many Linux users who use systems which would be capable of running Windows 10.
Display Configs Pgs 5-7 https://www.amd.com/system/files/documents/radeon-vii-quick-start-guide.pdf
I have exactly the same problem with my Radeon vii! but i have a question for you, did you use DP to HDMI cables? if yes, did you try to use only monitors who have DP ? i have 1 monitor who have DP and 2 monitors who have hdmi, so for those two i need to use HDMI to DP and those to are not working, but the one who have only DP is working fine, and i wonder if we use only DP monitors it will works?
ps. sorry if my english is very bad