Brotli has a static dictionary heavily geared towards web formats, and there really is no reason to use brotli outside of web stuff: the point of brotli is that it has browser support and does 15~20% better than gzip.

It's not bad per-se, but if you're not constrained to the web zstd will have a better compression ratio at every throughput (and better throughput at every compression ratio), and if you want maximum compression period it's not close to competing with LZMA-based formats (xz, lzip).