I bought a UGREEN 8K Dual HDMI 2.1 KVM switch with dual input and dual output. Unfortunately, only one of my monitors works. If I swap the HDMI cables between the monitors, the other monitor lights up instead, so it seems to work only with a single HDMI output at a time.

I had a similar issue with my previous KVM, so I initially thought the KVM was the problem. Has anyone else encountered this issue, and how can I ensure both monitors work in parallel?