Interesting! Like the LEGO blocks concept in your description.

KubeBlocks helped me to build my database infrastructure in just a few minutes. It really surprised me a lot lol

One Operator that can manage multiple types of databases, complete with comprehensive operations management features. How is this achieved?

Most Operators can only manage one type of database, or at most, several CRDs.

Each database has its own characteristics. I highly doubt that one operator can manage many different types of databases well. How are the differences between the databases handled?

Maybe, you can try KubeBlocks out to see how it managed to do this. https://github.com/apecloud/kubeblocks