xz got a bit of hype there about 10 years ago, I used it until a couple years ago when I noticed how slow it was with huge DB dumps and how much faster zstd was while still having decent compression.

So I have no idea about all this low level stuff, I just know that zstd is overall better for sysadmins.

But next time I'm doing any sort of scripting that involves compression I'll take a look at squashfs now due to this thread.