Question about AMD Ryzen 3 3300X

All mainboards with the B350, B450 and x570 chipset work (however, the B 350 and B 450 boards need a bios update).
B550 boards are supposed to come this year, but you'll have to wait a little longer for them.

It's probably no longer relevant, but Gigabyte's B450m ds3h doesn't need a bios update and should be perfectly fine for this motherboard.

Gigabyte B450M DS3H (AM4, AMD B450, mATX)