Android Preferences DataStore vs Existing Room Implementation

The official blog post you linked has a section specifically about Room vs DataStore:

If you have a need for partial updates, referential integrity, or support for large/complex datasets, you should consider using Room instead of DataStore. DataStore is ideal for small , simple datasets and does not support partial updates or referential integrity.

User preferences almost always fall into the 'small, simple datasets' that can be easily expressed as key/value pairs (or something more complicated if you want to use the Proto DataStore) that do not need the overhead of a table schema, SQL queries, custom parsing, or the 'relational' part of a relational database.

The problem with datastore is you cannot just fetch or update a part of data from a list like you can with SQLite libraries such as Room. This is true for both Proto and Preferences version. So if you have 10 thousand elements and you save them to DataStore and then you want to update 2 of them based on a condition you'll have to fetch the entire list, manipulate it and put it back. Here Room (or any DB solution) will be a way to go

But if you just want to save user preferences or small data it would be an overkill to use a DataBase - here DataBase Proto will actually be the perfect choice