Hi,
The cooking compression has performance implications for loading, we have disabled this for almost all platforms until those issues are resolved.
Compression of the pak file is a much more optimized code path this is what you should use. To do that enable compression and also enable store files in single pak file.
Or if you are creating a package from the editor then just use file → package.
You can see the compression amount using the unrealpak tool to uncompress the built pak file.
Thanks