I am building a Streamlit-based app on Databricks that allows users to:

1. Upload Excel scenario files
2. Store them in DBFS (e.g.,/FileStore/SCO/scenarios/)
3. Trigger a simulation/optimization model using the uploaded/stored file as input to the model 
4. Store the outputs (logs, visualizations, result summaries) in DBFS or Unity Catalog

Issue: When deploying this as a custom Databricks App , I run into restrictions:

• I cannot write to /dbfs/...directly from inside the app
• dbutils and the Databricks CLI are not available

I wan to know :

• What is the correct, supported way to write files from a Databricks App particularly streamline into DBFS?
• Is there a built-in API method or recommended workaround?