idiomatic-gradle VS samples

You should look into how https://github.com/jjohannes/idiomatic-gradle and similar projects handle it (nowinandroid has a good set up as well).

And finally, look at the idiomatic gradle repo. There is also a free video series that goes with this Understanding Gradle – Video Series. There are lots of bad practices in gradle that will slow your builds down, like using allProjects {}

I'd suggest getting rid of buildSrc, and just using build composition. I mentioned in another response, but check out https://github.com/jjohannes/idiomatic-gradle for how to use precompiled script plugins that are connected to the project via includedBuilds. The only issues I've had with this are generally resolved by just running the sub-build independently to resolve any caching issues in the 'primary' build. A simple gradlew build --settings-file ./build-logic/settings.gradle.kts run will generally resolve that, and that issue seems largely because of the 'root' build being a peer or anscestor of the included build (due to legacy structure of the project, an issue the linked example repo does not have).

When we initially migrated from buildSrc to an included build, it seemed an elegant solution to the problems outlined above. We were dropping buildSrc, with all its problems, and using the modern facility that Gradle considers the preferred, idiomatic replacement for buildSrc. (For a very elaborate example of this, see the idiomatic-gradle repo by former Gradle engineer Jendrik Johannes.) Included builds are indeed the best of both worlds in many ways: they can exist under version control in the same repository as the build that uses them; they can be easily opened in a separate IDE instance, improving build engineer productivity; they don't have the automatic test behavior of buildSrc, which improves feature engineer performance; and they're generally very well-behaved, without any of the magic of buildSrc.

If you're relatively new to this, I would recommend checking out the JavaFX documentation at https://openjfx.io/openjfx-docs/#maven and starting from the samples: https://github.com/openjfx/samples/tree/master/HelloFX/Maven

i also replaced the build.gradle file contents with what the openJFX suggested i changed it to. then i sync'd it after changing the javafx version in that .gradle file to 17.0.1 instead of 16.

An example pom file (maven) for a JavaFX program looks like https://github.com/openjfx/samples/blob/master/HelloFX/Maven/hellofx/pom.xml

Yes, JavaFX is a pain to configure. I'd recommend using Maven or Gradle with the JavaFX plugin to manage your application, that way you don't need to download and configure the entire OpenJFX SDK. There are samles for both Maven and Gradle in the repo you linked, so I would try them out. Note that only the Gradle sample includes a wrapper, so if you try the Maven sample you'll need to install Maven first.

Non-modular project (i.e. not using java modules): https://github.com/openjfx/samples/blob/master/CommandLine/Non-modular/Gradle/hellofx/build.gradle

example maven no modular project structure here https://github.com/openjfx/samples/tree/master/IDE/Eclipse/Non-Modular/Maven/hellofx/src/main