What’s the best way to handle complex environment configurations in App Service?

I'm working with an ASP.NET Core app that utilizes appsettings.json for its default values, which we then override using environment variables for different environments. Our Terraform deployment sets up over 30 environment variables at the app service level, and keeping track of these is becoming a bit overwhelming since environment variables lack the structure that YAML or JSON provides. Unlike Kubernetes, where we can use structured configmaps and mount them as files, we're limited with App Service to using just environment variables.

I've been considering a few options:
1. Have Terraform pull structured YAML or JSON from our config repo, then map it to a flat list of environment variables. This would certainly make the config easier to maintain in the repo, but we'll still have to deal with a long list of flat env vars in Terraform plans and App Service configurations.
2. Use Azure App Configuration to store our JSON config. However, I'm not convinced this offers much difference in terms of management.
3. During the deployment pipeline, we could mount appsettings.json from our config repo directly to the app service.

I'm leaning towards option 1 for the short term and considering option 3 for the long term, but that may require some testing and adjustments to our deployment pipeline. What are your thoughts?