React native custom buildType not using metro - react-native

Question

I need to build the same app to different applicationIds so that I can publish it on the Play Store / App Store as private applications for some of the customers of my company.
I decided to use react-native-config, as it should allow me to change applicationId and some env variables easily.
I have created some .env.${variant} files, that is, in the following examples, .env.customer1.
I have set the needed buildTypes as follows:
...
buildTypes {
debug {
...
}
customer1 {
initWith debug
applicationIdSuffix "customer1"
}
}
I forced react.gradle not to bundle when building with these variants
project.ext.react [
bundleInCustomer1: false,
devDisabledInCustomer1: false
]
Then I use this command line to run on my physical device
copy .env.customer .env && react-native run-android --variant=customer1 --appIdSuffix 'customer1'
The result is that the app is built and launched on my device, but what I see is an old version of the app (probably the last one that I have built using assembleRelease, some weeks ago), metro getting launched but telling me this when I try to force a reload, otherwise telling me nothing
warn No apps connected. Sending "reload" ...
I tried without any success
gradlew clean
npm start --cache-reload
npm cache clean --forced
npm i
Building the app without any variant (thus using default debug) correctly works.

Answer 1

Thanks to this answer, I've succeeded in solving my issue.
Instead of using buildTypes now I'm using flavors.
So,
android {
...
flavorDimensions "standard"
defaultConfig {
applicationId "com.stackoverflow"
...
productFlavors {
customer1 {
applicationId "com.stackoverflow.customer1"
dimension "standard"
}
}
}
and launching via
react-native run-android --variant=customer1Debug --appIdSuffix 'customer1'