Just to add one crucial detail regarding Daisy Chaining via DisplayPort: for MST to pass the signal to the second display, the chain needs to go specifically from PC to DP-In on Monitor 1, then DP-Out on Monitor 1 to DP-In on Monitor 2. Also, as mentioned, you will definitely need that USB-B upstream cable running from the PC to the first monitor for the KVM side of things to actually work. Just make sure to check the OSD settings on the main monitor to ensure MST/Daisy Chaining is toggled on, as it is often disabled out of the box.