logainofhades :
The lower range 300 series boards are readily available now. 4 monitors is easy with a dedicated GPU. Ryzen APU, in a B350 Pro4 can run 3 monitors. I am just unsure if the APU can run 3, and a dedicated GPU also be used to run 3. I have not been able to find a definitive answer on that one.
I'm speaking of lower end, mainstream, boards for Intel systems, of which I realized that Newegg's search is slightly flawed. So, yeah. I made a mistake. The B360, H370, and H310 Intel boards are available. So a low cost i3 is on the plate. In fact, the i3 is what I recommend, mostly based on single thread performance. It doesn't seem like you'd be using programs that are heavily multi-threaded, so you should see an advantage from the i3. The 8100 is basically what a last gen i5 was anyways, You'll be more than happy with it.
I do have to say that I simply can't find a better video card for a 6 monitor setup than the one I linked above. If you want to use 6 monitors then that is the best way to go. If you are happier with 4 monitors then the majority of graphics cards would be up to that task. Many cards have at least 4 outputs in a mix of DisplayPort and HDMI.