I just did a fresh install for a RX 580 Nitro+ 8GB card. In the Relive software it says Freesync not supported. I have used it before with the same model card without a problem. It is enabled in my monitor.
Sapphire Nitro+ RX 580 8GB
Ryzen 3 1200
AX370 Gaming K5
Samsung CF390 Curved 24" Monitor
W10 64 bit