Presumably, old desktop and new desktop is connected to router via a wired network.
As an alternative (and also experiment whether it will work to begin with), is to assign a static IP address first to the old desktop with the subnet 10.1.1.x (outside of the DHCP server range) to see whether your network access from old desktop to new desktop is good to go.
You should check to see if the Huawei router has any function to block access. It might be by MAC address of the device so you would then have to enter the MAC address of old desktop; assuming the static IP address experiment worked as per your expectations.
Any chance you disable the router DHCP temporarily and check if your ESXi hosts get IP rom your DHCP VM? If that works you should decide with DHCP to use, since you cannot have two DHCP active in your network.---
Senior Infrastructure Specialist