PCE-AX3000 only supports PCI-Express x1 standard, if you have a PCI-Express x1 slot available on a windows PC, it is sufficient.
ASUS ROG STRIX B550-A GAMING motherboard has 3 of PCIe 3.0 x1 slots, which are backward compatible to PCI-Express x1 standard.
So, if you are upgrading to Wi-Fi 6/ax, do not look further, ASUS PCE-AX3000 is the best price, best quality product available on the market today !

Yes, it should be compatible.
I would recommend it, I haven't tested wi-fi yet but Bluetooth is great.