SourceSet with name 'main' not found

I finally found a solution!
I was doing a few things wrong, first, both dokkaJar and sourceJar tasks have to be in the main build.gradle and not inside deploy-bintray.gradle.kts. Moving them made it work and fixes:

SourceSet with name 'main' not found.

Secondly we cannot use from(components["java"]) because this is an Android lib so I’ve replaced that line with artifact("$buildDir/outputs/aar/${artifactId}-release.aar").

Last but not least, as stated here (step 7):

“Also, the POM file generated does not include the dependency chain so
it must be explicitly added…”

I had to add this:

pom {
...
    withXml {
       val dependenciesNode = asNode().appendNode("dependencies")
       configurations.getByName("implementation") {
         dependencies.forEach {
            val dependencyNode = dependenciesNode.appendNode("dependency")
            dependencyNode.appendNode("groupId", it.group)
            dependencyNode.appendNode("artifactId", it.name)
            dependencyNode.appendNode("version", it.version)
         }
       }     
    }       
}