Ok, maybe I am not able to boot because this image is not for the stock PocketCHIP but for one which requires a custom breakout board:
https://github.com/armbian/build/pull/7647
Maybe I could have found that out sooner if there was a device page for this custom PocketCHIP in the community supported devices page at ttps://www.armbian.com/community/. Who/how is supposed to create it? The board maintainer? How is one supposed to do that? There is no mention in the Board Maintainers Procedures and Guidelines. I haven't anything on the armbian github repositories about the boards information on this page.
It would be important to have the device page, especially when the image was created for custom developed PCBs. Only after some digging and finding the PR where the device was added, I was able to figure out why I may not be able to boot the pocketchip-sd armbian image.
Paulo Carvalho's post in Boot hanging on Pocketchip sd trixie 6.18.20 minimal Latest 26.2.0 trunk.668 at "Starting Kernel ..." was marked as the answer