@arvind-1 ,
for your scenario, I suggest using Apache Sling Context-Aware Configuration

The application needs different configuration for different sites, regions and tenants = different contexts. Some parameters may be shared, so inheritance for nested contexts and from global fallback values is supported as well. You have full control which content subtrees are the contexts in your application, the structure above is only an example.
Using the Context-Aware Configuration Java API you can get the matching configuration for each content resource without caring where it is stored or how the inheritance works.
full documentation can be found here: https://sling.apache.org/documentation/bundles/context-aware-configuration/context-aware-configuration.html
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However, if you really wanted to use OSGI configurations, then what you can do is to create your OSGI configuration with your language variations, for example:
- eng.subscriptionApiKey
- fr.subscriptionApiKey
And then using AEM backend, to detect the language from the SlingHttpServletRequest object, and either output eng.subscriptionApiKey or fr.subscriptionApiKey.