There's not an _easy_ way to do this right now. Your best bet is a lossless transform that undoes the huffman coding in the zip files, converting the compresse

There's not an _easy_ way to do this right now. Your best bet is a lossless transform that undoes the huffman coding in the zip files, converting the compressed streams from effectively uncorrelated bitstreams to largely similar byte streams, and then pass that through a large-window compression algorithm (zstd?). Similar techniques are used in ChromeOS for delta updates.