I went with Dfrobot [1] because they also sell a case (and it is all in stock). Had the CM4 already. I wouldn't have minded another one if I could've 3D printed the case but I didn't find such. Btw, I did have to go from 3 to 2 ports.
Right now it is hooked up on my switch. I intend to put it between my desktop and my switch and run some iperf3. Because I'll get fiber soon, and I'd like to be able to saturate that.
CM is the computer module, right? what kind of "board" do you use the CM4 with to use it as a router?