I'm not clear on what's connected to the dock and what's connected to the KVM, or how they're connected together.
Try disconnecting everything from the dock except ethernet. Use your P40 display and keyboard for troubleshooting. I don't think the monitors would cause an issue but it's best to eliminate all variables. If the same thing happens then you can reconnect everything.
Disconnecting everything from the dock and leaving only power and ethernet connected didn't help. But I did discover something interesting during the process. The problem only appears to occur if I reboot using 'Start Button' > 'Power' > 'Restart'. However if I reboot via 'Start Button' > 'Power' > 'Shut Down', and then manually power the machine back up, then it boots up fine even with the ethernet cable connected to the dock. Could this be related to differences in 'Restart' and 'Shutdown - Power Up' functionality, like power up sequencing?
Have you confirmed that everything connected to your system is UEFI-capable? If not, this can break the boot process.
On the networking side, that's difficult to answer without knowing your exact network layout, router config, etc. Plus, that can go down a long path trying to diagnose remotely. I'd start by looking into router settings for NAT, DHCP, IP assignments and things of that nature. It sounds like you can get an IP assigned once booted into Windows, so that's a plus. Also check your network addressing protocol once booted. If it's IPv6 then try disabling everything IPv4 related since that's a legacy protocol. Ideally you want to move up to IPv6.
I have not tried these yet as I am not familiar with the process of validating UEFI capability and addressing protocol, but I could start digging into these if the Restart / Shut Down differences don't result in any solutions.
Really appreciate your help Erik.