From analyzing data using Data Science methods to building E2E Big Data Platforms, Big Data Analytics covers a very broad of different use cases and technologies.
Integrating data in a heterogenous software stack, compressing information, structuring unstructured data. Data Engineering can be a part and also a challenge in Big Data itself.
There's no project without issues. Troubleshooting is the most important and toughest challenge because it can impact the projects success.