Building Kotlin TornadoFx into exe for Windows - kotlin

Question

I have an application written in Kotlin and I used TornadoFx to build a GUI around it. As stated in the TornadoFx guide, I used OpenJDK11 and set kotlin.jvmtarget to "11". Here is my gradle build:
plugins {
id 'org.jetbrains.kotlin.jvm' version '1.4.30'
id 'application'
id 'org.openjfx.javafxplugin' version '0.0.9'
id 'java'
id 'edu.sc.seis.launch4j' version '2.4.9'
}
group = 'me.nicola'
version = '1.0-SNAPSHOT'
repositories {
mavenCentral()
}
application {
mainClassName = "Engine"
}
javafx {
version = "11.0.2"
modules = ['javafx.controls', 'javafx.graphics']
}
dependencies {
testImplementation 'org.jetbrains.kotlin:kotlin-test-junit'
implementation 'no.tornado:tornadofx:1.7.20'
implementation group: 'org.apache.commons', name: 'commons-email', version: '1.5'
implementation 'com.github.doyaaaaaken:kotlin-csv-jvm:0.15.0'
}
test {
useJUnit()
}
jar {
manifest {
attributes "Main-Class" : "EngineKt"
}
}
compileKotlin {
kotlinOptions.jvmTarget = "11"
}
compileTestKotlin {
kotlinOptions.jvmTarget = "11"
}
task fatJar(type: Jar) {
baseName 'PrimaNotaHelper'
manifest {
attributes "Main-Class": "EngineKt"
}
from {
configurations.runtimeClasspath.collect {
it.isDirectory() ? it : zipTree(it)
}
}
with jar
}
launch4j {
mainClassName = 'EngineKt'
//icon = "${projectDir}/icons/myApp.ico"
}
I'm trying to use Launch4J to bundle my app into an executable for windows (.exe) and it compiles correctly when I launch the "launch4j" task, building the "lib" folder and the exe file. However, once I'm on Windows the executable does not work.
I also tried to use the Launch4J GUI for Windows and played around a little bit with that but nothing works for me: either It simply crash before starting or ask me for a different version of the JRE.
Can someone help me to set up my build correctly?
Thank you so much!