Reporting in that I’m having the same issue with my AMD framework 13 Win11 using a Chinese no-name amazon monitor https://www.amazon.ca/dp/B0CMHKBJKF
“No input” when display is plugged in via USB-C to the framework. Tried every port. Tried a bunch of different cables (Thunderbolt 4/USB 4 certified, 100W/240W PD, 10gbps/40gbps).
Monitor works perfectly fine with every single other usb-c device in the house, including an old laptop from 2016 (MSI GS60 6QE), a Macbook Air M2, two Win10 desktop computers, a 4th gen iPad Air, and a Samsung S22 Ultra. All devices report the proper resolution, so the monitor and cables I’m testing definitely works.
Weirdly enough, as said by others, when plugging the monitor to a power source first (like a USB-A, another USB-C, etc) it will work with the framework. Also if the power source is unplugged after the screen is on causes it to turn off, then on again and “no input”. Using an HDMI cable will also work. The monitor itself consumes about 5W/1A when using 5V.
Plugging the monitor into a usb-c PD charger first will actually negotiate a 20V and subsequently charge the framework (although the monitor doesn’t draw more than 33W/1.66A).