Using local maven repository without modifying gradle scripts in project

init.gradle.kts

initscript {
    // Enter a local Maven server URL.
    // Hardcode or get from system property.
    val localMavenUrl = "" 

    // This affects the repositories configuration
    // in the buildscript block of the top-level build.gradle(.kts).
    gradle.rootProject {
        buildscript {
            repositories {
                maven(localMavenUrl)
            }
        }
    }

    // This affects the repositories configuration
    // in the pluginManagement and dependencyResolutionManagement blocks of settings.gradle.
    gradle.beforeSettings {
        pluginManagement {
            repositories {
                maven(localMavenUrl)
            }
        }

        @Suppress("UnstableApiUsage")
        dependencyResolutionManagement {
            repositoriesMode.set(RepositoriesMode.PREFER_SETTINGS)
            repositories {
                maven(localMavenUrl)
            }
        }
    }

    fun isWindows(): Boolean {
        return System.getProperty("os.name")
            .lowercase()
            .contains("win")
    }

    fun String.valueOf(className: String): Any {
        return Class.forName(className)
            .getDeclaredMethod("valueOf", String::class.java)
            .apply { isAccessible = true }
            .invoke(null, this)
    }

    fun String.toVariable() =
        if (isWindows()) this else valueOf("java.lang.ProcessEnvironment\$Variable")

    fun String.toValue() =
        if (isWindows()) this else valueOf("java.lang.ProcessEnvironment\$Value")

    fun setSystemEnv(fieldName: String, key: String, value: String) {
        val field = Class.forName("java.lang.ProcessEnvironment")
            .getDeclaredField(fieldName)
            .apply { isAccessible = true }
        @Suppress("UNCHECKED_CAST")
        val env = field.get(null) as MutableMap<Any, Any>
        env[key.toVariable()] = value.toValue()
    }

    fun setSystemEnv(key: String, value: String) {
        setSystemEnv("theEnvironment", key, value)
        if (isWindows()) {
            setSystemEnv("theCaseInsensitiveEnvironment", key, value)
        }
    }

    // Override the GRADLE_LIBS_REPO_URL of DefaultGradleApiSourcesResolver
    setSystemEnv("GRADLE_LIBS_REPO_OVERRIDE", localMavenUrl)
}