As promised pics of my setup.
New monitors ready to be unboxed:
Before:

(bottom of rack where PCs are)
After:
Basically main thing that changed is the KVM got moved from downstairs to upstairs, along with cleaning up cables a bit, which involved taking everything out and starting it from scratch.
Also have my work PC setup with all of this. For now, the two new 4k monitors (sides) will be dedicated to work. I was going to use one as my main so I can enjoy it on my personal machine too but the work PC uses display port and the KVM is HDMI and the adapters did not handle 4k. But the main thing, when I tested the 4k on the KVM, it worked for both my Linux machine and my gaming machine. I was a tad worried that for a reason or the other it would not work. Like incompatible cable or something like that. But thankfully it's not the case.
Made a video of the process of dismantling and rebuilding everything, will probably edit that tomorrow.