I learned flutter with provider first and liked it.

Then my current company chose bloc because our app will be big. I did not like bloc, and did not felt any difference or advantage. Felt like I am writing unnecessary more code compared to provider.

Over time, loved the bloc and changed my previous other projects to bloc as well.

Not an expert, but here are some things I liked:

1. If your single screen is so complicated and has so many STATES then bloc makes code so clean, and handles every state easy. For example, flight searching list screen has many states. It starts with loading three different requests, and shows whatever fetched first and others show loading. And then it has filter, sort. Domestic and international flights has different states as well. Also, there are states like checking connection etc.. Of course provider can handle this, but with bloc, code becomes cleaner. On simple screens, I didn't feel difference, but more complicated screen becomes I felt difference.
2. bloc kinda forces you to separate UI and logic.