There’s a comparison of different compression algorightms here: Squash Compression Benchmark
According to it the fastest decompression can be achieved with lz4f codec. What is it though? How can I use it? I can’t find anything about it, other websites mention lz4 and lz4hc, but not lz4f.
See: GitHub - lz4/lz4: Extremely Fast Compression algorithm
For lz4 functionality in Linux see man lz4 