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.