I have the source code of an application and wanna modify the source code a bit and build an APK out of the customized source code for personal use.
Problem: I cannot use Android SDK and/or Android studio.
Situation: I have the source code and have modified it. The source code is in Kotlin.
Desired solution: An online compile tool to upload the source code and download an APK.
Not sure if is what you are looking for, but the Microsoft AppCenter is a tool that may fit your needs. It allows you to connect to your source code repo, build your app in the cloud and either release to the app store or download the package.