It depends on the complexity of the elements in page. If the scenario involves interaction with elements in multiple pages, or a single page having too many elements then itâs better to split into multiple step definition classes. This will help out in maintaining your tests well versed
Currently working on a PoC for BDD with Specflow + NUnit so my take always are
1. Multiple scenario with single Feature file
2. Common Step definition file for generic functions
3. Generic file for handling utils functions