Feedback from Aurelio:
  -c, --compress=2 Enable compression of resources (level 2)

The help message mentions "level 2" but not clear to the jlink user of what level 2 means and what is a valid level value (e.g. 300?). Such information is in jlink --list-plugins option. In fact the difference may not be obvious when it should 0, 1 but not 2.

Perhaps -c == --compress (no level is specified).

Plugin Name: compress
Option: --compress=<0|1|2>[:filter=<pattern>]
Description: Compress all resources in the output image.
Level 0: constant string sharing
Level 1: ZIP
Level 2: both.
An optional filter can be specified to list the pattern of files to be filtered.
Use ^ for negation. e.g.: *Exception.class,*Error.class,^/java.base/java/lang/*