Mad respect. I tried extracting a clean .o file out of a statically linked ELF once, and it's an absolute nightmare. How are you handling switch tables and indirect jumps? Without dynamic analysis, it's sometimes physically impossible to figure out what a register is actually pointing to
I have analyzers that resynthesize relocations from the contents of the Ghidra database, no custom annotations required. They evaluate relocation candidate spots through primary references and pointers/instructions and emit warnings if the math doesn't check out.
It does require a reasonably accurate Ghidra database to work properly, but I've had users delink megabytes of code and data from a program successfully (as in, relinking it at a different address results in a functionally identical executable) once they've cleaned it up. The accuracy warning in the readme is mostly because it's really complicated to describe exactly what inaccuracies you can get away with, there's a fair amount of wiggle room in reality as long as you know what you're doing.