I am also having issues booting the CM4 in the carrier, but it runs fine with Raspberry Pi OS Lite in the official compute module 4 IO board. I will try to prepare a boot USB and see if it is able to boot from that.
I am having a similar problem as well. I changed the default IP on the LAN port from 192.168.2.1 to 10.0.0.1, and I’m assuming the Pi rebooted after that. I could no longer access it through LAN and didn’t know what was wrong until I was able to get an HDMI Micro cable and hook it to a monitor. My output looks different than yours and ends in a “Please press Enter to activate this console” message. However I haven’t found a keyboard yet that will work with this mini-router. None of my keyboards even light up even though the Pi outputs that it does detect it.
Did you ever find a solution to this issue or not? I made a post of my own and also emailed Seeed support but I feel like I have a $149 brick now. I only got to play with OpenWRT for literally about 20 minutes before it stopped working.
Follow this guide to install to eMMC, however instead of grabbing the latest image, grab the 2021-11-19 factory image, and then after it’s installed and has booted up, then grab the latest sysupgrade image to update the box from the GUI. Worked for me.