Try a DP (from your RX570) to HDMI (your monitor) cable rather than an adaptor. I had the same HDMI and DVI output-to-black screen issue which I just couldn't resolve, and the only fix was using the RX580's DP-out, so I initially bought a DP-to-DVI adaptor.
Although the adaptor worked for Mojave (and Linux), I also had the same problem as you with Win 10 and the adaptor i.e. blinking black for 5 seconds, then showing the Win 10 login screen for 1 second, before blinking off again. The guy in the PC store said it's a power-delivery problem for some adaptors. Whether that's correct or not, going to a cable fixed it.