Hi Anton,
I went through dukehoff-decide properly before answering, so some of this is about your code rather than ours. Both adapters are workable. One blocker first, then your four questions.
pom.xml sets maven.compiler.release to 21. Models requires Java 25 or newer — the stack is
built on a 25 toolchain and uses the Vector API and the FFM API, so this is not a "works anyway"
case; the class files will not load on 21.