See the line:
RuntimeError: Failed to load icu with error: /home/pi/opt/calibre_source/calibre/src/calibre/plugins/icu.so: undefined symbol: usearch_first
That means that the linker could not locate the usearch_first symbol in your ICU DLLs.
http://icu-project.org/apiref/icu4c/...fee8473e0353d4 You can use
LD_DEBUG=all
to get more information. But most likely the linker is picking up some stub ICU library from somewhere.