You could try and publish your library with module metadata generation disabled, like so:

tasks.withType(GenerateModuleMetadata) {
    enabled = false
}

and see if this lets you consume your artifacts in your project.

(Source: https://docs.gradle.org/current/userguide/publishing_gradle_module_metadata.html)

Nice library btw, read your dev.to post!

Btw. your project is not too contributor friendly.

For example it requires to either change the version catalog or have a specific Amazon Java installed as it is also not auto-provisioned.

And even publishing to maven local requires signing configuration

Anyway, your main problem here is, that you are not reading your build output. 😉 You have several > Multiple publications with coordinates '...' are published to repository 'mavenLocal'. The publications 'jvm' in project '...' and 'kotlinMultiplatform' in project '...' will overwrite each other! which is the source of your problem most probably. In your build scripts you nail group/artifact/version of all publications to the same value, causing this warning and thus problem. You should at least remove the setting of artifact, then it probably works as expected. But actually I would also remove setting of group and version and better set it on the project instead. I think by just doing it on the publication, you for example cannot conveniently use the project in a composite build without manual substitutions. Also, disabling GMM as @Thomas Keller suggested would not change anything in this case.