yeah, ok. So I just went back to test the S3 Sleep power state option, and switched it to the Windows’y one, which the BIOS says Linux supports and it does, but now the machine seems to still burn battery when it’s suspended … So, I have found the larger culprit.
Adding support for zstd is a fine move. None of this should be interpreted like that first comment of being due to “xz having a smell” about it. That is FUD, and this same kind of situation could happen to countless projects.