I really don't know the complexity or the way to go forward. Any help is appreciated.
The ZipFile
class contains all what you need:
zf = ZipFile(...)
# for all files
for zinfo in zf.infolist():
print(f'{zinfo.filename}: offset {zinfo.header_offset}')
# for specific file
zinfo = zf.getinfo(filename)
print(f'{zinfo.filename}: offset {zinfo.header_offset}')