Forget about trying to create a single executable jar that includes JavaFX components and depends on a pre-installed JVM (it is not a supported configuration).
However, cwellm's answer here details a method that keeps the modular JavaFX dependencies separate from the created application jar by keeping the JavaFX modules in separate jars added to the module path, I believe that this might be a valid and supported deployment configuration. It does require deploying multiple jar files to the client in the right locations in order for it to work. Another alternative would be to assume a distribution of the JDK such as liberica or corretto which can come with JavaFX included in the base JDK distribution, then you don't need to specify a module path for JavaFX as it will already be present in the default boot module path for the JDK.
Recommended Solutions
Instead create a runtime image using jlink, this can be done by (among other methods) using the openjfx maven plugin.
Or if you want an installer, use jpackage which can also (among other methods) be created using maven, see JPackageScriptFX as an example.
jpackage doesn’t create archlinux native packages. So if you want that, then jpackage wouldn’t be the thing to use. Instead you could use a maven assembly or tar call to create a zip or tar.gz of the jlink output, or use the pacman tool to create a native archlinux package of the same.
Or if you like gradle see the badass jlink and runtime plugins.
Using a build tool (maven or gradle) to include the JavaFX dependencies rather than relying a JavaFX sdk download is preferred IMO. Also, if possible, define a module-info. Then jlink can be used to create the required runtime from your app, it’s dependencies and the jre, as well as the execution script for the app, so that things are self-contained. Native packages in rpm or deb format created by jpackage takes this further. Installing apps packaged this way also ensures all required OS lib dependencies are correct.
If you want to understand more see the contextual info (FAQ section) in this answer: