Review on 📺 Koopman 4K HDR HDMI Switch - 3 Port HDMI 2.0 Switcher Selector Box with Remote, Dolby Vision HDR10 Support - Perfect for PS4, Xbox, Apple TV & More! by Austin Wolf

The most important lesson I've learned is that you can't assume that a cable that works when plugged directly into a monitor will still work when in use this switch works. And that's a good thing, but it definitely means you have to be careful when choosing your cable. I had an old HDMI cable which I plugged into both directly into my PC (brand new with a GTX 1660 Ti) and via a manual 2-port switch with no problem. I needed to connect a third device, so I ordered this one, mainly due to the form factor and the fact that all the cables are plugged into the back of the device. Strangely, my M1 Mac Mini and Dell 2-in-1 laptop worked fine, but my desktop PC showed no signal. I tested two other devices with the same cable and both worked fine. I was about to return it but then thought it might be a good idea to try a new cable as I found I had to buy new cables when I upgraded my home theater a few years ago. Luckily I had a spare cable. Cable I bought back then and when I tried it it worked great. I don't know enough about how it works to understand why a cable would work that would work when connected directly or through another junction block, but that's how it works. Plus it's a cute little switch. I didn't have to use the power connector, FWIW. The remote control works well too.