Ruby is awesome. Focus less on particular language and instead think about what you want to do and then use whatever has the most libraries/utilities for the particular use case. I used to think in these terms but it isn't the right question.
If I'm just making something from scratch I might reach for Rails, which I love and am super comfortable developing in. If I am doing a lot of data work with something that also needs a web app/web API, I might reach for Django or FastAPI depending on project bandwidth. It just depends. What are you trying to build? Tell us more.
Just my $0.02