MSI HDMI is not working

Solution 1:

After the addition of the GPU output panel…

What you appear to have are 1 DVI-D, one HDMI & 3 DisplayPort connectors.
It is unlikely that all those will work simultaneously, some will be shared, but it is very likely one of each type will work [& possibly two of the DisplayPort connectors].

So - you cannot directly connect two HDMI cables - there's nowhere to put them. Your earlier picture of the motherboard's video outputs are probably connected to nothing internally. They are designed for CPUs with onboard [APU] graphics, which your Ryzen 5 1600X doesn't have.

What remains to you are those direct connections from the PCI graphics card.

If either of your displays has a DisplayPort or DVI-D connector, then that is the obvious first choice. Buy a simple cable to match.
If they only have HDMI, then you will need a converter, from DVI-D or from DisplayPort, to HDMI.

Previous answer, before we had full details…

You cannot "split" HDMI into multiple independent signals. As you've discovered, a 'splitter' cable just duplicates the same image to two displays.

You will need to use a DVI-D cable to your other monitor, or get a DVI-D to HDMI converter if the display can't take DVI-D.