Then to use it for stego just take your headerless ciphertext and decompress it. Tada: you get model output. To decode the stego just compress it. Assuming everything was built right and that your ciphertext is uniform, the output should be indistinguishable from the model just sampling using an RNG.
As a bonus, you don't even have a stego tool on your computer you just have a particularly carefully constructed text compressor and decompressor that is perfectly usable (and even state of the art in compression rate, given a big enough model) for the compression application.
