First, clear the CMOS by unplugging the PC from power, removing the CR2032 battery, pressing the case power button, waiting a couple minutes, putting the battery back in, plugging the power and trying to turn on the PC.
Connecting the monitor to the motherboard can't produce a picture because the Ryzen 3600 does not have an integrated graphics chip. Only the CPU-s ending with a G have integrated graphics on AM4, for example the 5600G or 2400G.