TESmart HD202-X24 Dule monitor failure with PC setup

I am still trying to resolve a monitor issue and could use your help.

Here is all the information I have and what steps I've taken.

The hardware: 
TESmart HDC202-X24
Gigabyte M32UC
BenQ PD2705U
Radeon RX 7900 XTX

The layout:

Both monitors are connected to the switch using 4kUHD HDMI cables, both about 1.2 meters or 2 meters max in length. I connect my laptop to the switch via the UCB-CI connect my PC to the switch using the USB-A to USB-B as instructed

I then have a 4k UHD HDMI cable from the switch to the graphics card HDMI port and a DP cable from the switch to the graphics card DP port

Problem:

When I use the laptop, both monitors work at the res 3840x2160 60MHZ.

When I switch to the PC unit, only the monitor that connects through the DP works (currently the Gigabyte)

What I have tried to fix this:

I tried shutdowns and unplugging devices and reconnecting in various orders but this failed.
I tried the HDMI from the graphics card direct to the monitor and it worked with correct res.
I tried a HDMI to DP 4k Cable and this worked except my res was capped to 1080p.
I tried using AMD Adrenaline to force the res change but this wouldn't work.
I tried a UGREEN 8K@60Hz DP to HDMI Adapter, but this failed and the screen was black again and I couldn't detect the monitor.

Adapter I bought 
(UGREEN 8K@60Hz DisplayPort to HDMI Adapter Active DP 1.4 to HDMI 2.1 Cable | 4K@120Hz Uni-Directional Display Port Male to Female Compatible with Monitor Projector HP Dell Asus AMD GPU NVIDIA

I've tried everything and googled, emailed the TESmart people but had no response. I'm out of ideas and really frustrated because all my hardware is fairly high spect and I spent a lot of money on the KVM Switch so I expect it to work out the box but it won't and I have no idea how if at all it's fixable.

I can't be the only one to have this problem so I'm hoping there is a solution that doesn't require me buying another expensive bit of kit :(

Thanks for any help.

Ben