Personally I prefer “camelCase” or “lowercase” for namespaces, but almost all packages use PascalCase for namespaces now. Having parts lowercase and PascalCase together in a project leads to confusion because people need to remember the case additionally to the name.
So, despite I like camelCase more I would vote - with a for PascalCase as it’s much more widespread and it may feel more familar for people coming from other frameworks. And integrated 3rd party components also do not that alian.
But there is also a good reason to stick with camelCase: Changing everything would make migration difficult.