The difficulty of a Databricks certification depends on your experience level and the specific certification you are pursuing. The Databricks Certified Professional Data Engineer certification is generally considered to be the most difficult, as it covers a wide range of topics in depth.
However, all Databricks certifications are challenging, as they require a deep understanding of the Databricks platform and Spark programming. The exams are also designed to assess your ability to apply your knowledge to real-world problems.