I am going through the data encryption documentation on ODK website. It says that if encryption is enabled, the dashboard and OData viewing feeds are kind of disabled (don't show the data except metadata).
My question is: How to, then, make PowerBI or any other visualization tool to show the data? Where to enter the decryption key? OR is it that all visualization/OData tools get disabled totally?
I am not aware of a way to decrypt as part of a connection to viz/OData tools. I think you will need to decrypt and download, then load the data to your tool (presumably after removing or anonymizing the sensitive data).
With R, it is possible to decrypt and load encrypted data using ruODK::submission_export, before further processing (e.g., data deidentification/anonymisation) and visualisation (still using R functions and packages). A similar pipeline can be developed with Python using pyODK.