I need to publish the same app multiple times with just some small differences (app name, app launcher icon, colors and images).
I will configure Gradle to have a different applicationIdSuffix for each buildTypes.
So the apps will have this kind of packages: "com.appname.app1", "com.appname.appB", "com.appname.app3", "com.appname.app1234", etc...
Is that allowed from the Google Play Store rules?
Yes. You can publish the apps by changing there package names.