Summary:
There are apps that won't run with Java 11 and therefore one should not use B4JPackager11 -> test that out carefully. It can be that you have a different active JRE than JDK though! Keep attention here, check in the console and launch the .jar file from the console with Java 11 to be sure.
Command for checking Java:
/usr/libexec/java_home -V
If the app is not running with Java 11 then
use B4JPackager instead (keep in mind that most probably the user needs to install the created installer in administrator mode)