How to install DMN-Engine-only as Jboss Modules?

Dear Camunda-Community,

I know that there is an Installation Tutorial for getting Camunda 7 Platform up and running on Jboss. But I do NOT need the Process engine. Instead I only need the DMN-Engine.
When I embed the dmn engine as described in Camunda 7 User Guide and integrate my maven module in a webapp that is deployed on a JBoss EAP 7.2, then I get the error as shown below on deployment of the webapp…
I found the following topic in this forum ( Starting a DMN Engine in a Bean does not work ) which appeared to offer a solution, but it presumes that the camunda modules are already present in Jboss. So is there a way to add exclusively the dmn modules or is there another way to fix my deployment problem concerning the javax.el.api Module?

Many thanks in advance,
Stephan

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Caused by: java.lang.NullPointerException at javax.el.api@1.0.12.Final-redhat-00001//javax.el.CompositeELResolver.add(CompositeELResolver.java:117) at [