ok, I was able to sysupgrade the 3rd A5-V11 to R18 image using my options above and was able to successfully extroot without blkid and I verified that /lib/libblkid-tiny.o exists.
In retrospect, it is possible I had an in-partially installed block-mount package when I was installing USB required pkgs manually one by one, and it all worked only when I generated a proper image containing the required packages, and nothing to do with blkid
That's the most logical conclusion, apologize for the time wasted looking at this and I updated my original post.
"Tiny" build -- meaning you've probably got a relatively ancient or underpowered router -- which either or both won't have enough flash and RAM to install and run wireguard, or enough CPU power for more than a trickle.
I'd suggest reading up on a new device and then, if you've got questions about specific units, searching on the forums here for opinions. If they aren't already answered, opening a new thread with your question would be a next step.
Many opinions on devices in the US $20-50 range (or less) that are likely going to be a better option for you in the long thread
