Then I upload the APK to Google Play Console, it says ( warning ):
This APK results in unused code and resources being sent to users. Your app could be smaller if you used the Android App Bundle. By not optimizing your app for device configurations, your app is larger to download and install on users' devices than it needs to be. Larger apps see lower install success rates and take up storage on users' devices.
Use the Android App Bundle to automatically optimize for device configurations, or manage it yourself with multiple APKs.
Oh wait it’s not actually blocking. It is actually just a warning. I was misleading other Play Store errors.
Oh no, wait again… Well I can’t really understand as it’s a warning (errors are now solved, they was symbolized by a red exclamation mark), but the “start implementation on the channel” button it’s still disabled.