maven-metadata.xml keeps getting requested on build/gradle sync

Everytime I run the app I see maven-metadata.xml and it seems to slow the build. It can take up to an hour each build/gradle sync. Have tried flutter clean, deleting .gradle cache in user/.gradle/cache, invalidate and restart, clean project, and restarting my pc.

Relevant code of app/gradle

buildscript {
    repositories {
        maven { url 'https://plugins.gradle.org/m2/' } // Gradle Plugin Portal
    }
    dependencies {
        classpath 'gradle.plugin.com.onesignal:onesignal-gradle-plugin:[0.12.1, 0.99.99]'
    }
}

apply plugin: 'com.onesignal.androidsdk.onesignal-gradle-plugin'
apply plugin: 'com.android.application'
apply plugin: 'kotlin-android'
apply plugin: 'com.google.gms.google-services'
apply plugin: 'com.google.firebase.crashlytics'
apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"

android {
    compileSdkVersion 30

    sourceSets {
        main.java.srcDirs += 'src/main/kotlin'
    }

dependencies {
    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
    // Import the BoM for the Firebase platform
    implementation platform('com.google.firebase:firebase-bom:29.3.1')

    // Declare the dependencies for the Crashlytics and Analytics libraries
    // When using the BoM, you don't specify versions in Firebase library dependencies
    implementation 'com.google.firebase:firebase-crashlytics'
    implementation 'com.google.firebase:firebase-analytics'

    testImplementation 'junit:junit:4.12'
    androidTestImplementation 'androidx.test:runner:1.1.1'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.1.1'
}

build.gradle

buildscript {
    ext.kotlin_version = '1.3.50'
    repositories {
        google()
        mavenCentral()
    }

    dependencies {
        classpath 'com.android.tools.build:gradle:3.5.0'
        classpath 'com.google.gms:google-services:4.3.8'
        classpath 'com.google.firebase:firebase-crashlytics-gradle:2.7.1'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
    }
}

allprojects {
    repositories {
        google()
        mavenCentral()
    }
}