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s/\G(?|(\0{16})+(?{'*'})|(.{1,16})(?{...}))/$^R\n/sgr  What you used.
s/\G(\0{16})|\G.{1,16}/($1?"*":...)."\n"/segr          Could be used.
s/\G.{1,16}/($&eq"\0"x16?"*":...)."\n"/segr            What I used.

#!/usr/bin/perl

...
}

print hexdump( path( $0 )->slurp );