What CPU do you have? If Ryzen, only the 2200G and 2400G will output video to the motherboard video I/O as they're the only Ryzen desktop processors with integrated graphics. I doubt you have either of those as they would bottleneck the GTX 2080. Put the video card in the top slot and retry.
X470-F, 2700X, 5700 XT Nitro+, 970 EVO, LanCool 2 Mesh Performance, H115i Pro, 16GB3000C14, TT650W Gold