Multiple builds of same app with different cordova id and icon / splash

I have an app which I publish for different customers. The apps are almost identical. The few things that are different can be easily controlled with an environments.xxx.ts for each customer. However each app does also need to have a different config.xml (because each needs a different widget id for the app stores, and slightly different descriptions) as well a different resources (icon and splash).

What would be the best practices to achieve this?

Right now I have an almost exact copy of the same project directory for each “flavour” of the app. Only the config.xml, package.json, icon and splash image differ. This is not nice at all.

Thanks.