Part of the pain is all the data movement. I see your data comes from ADLS originally. Does the Managed Instance add value for you?
There are a number of services to consider. Chief among them is Azure Synapse (Workspace). Everything big data seems to be converging in Azure Synapse. This includes Spark and Machine Learning. The linked document says it better than I can. It may be possible to replace both your Managed SQL and Databricks.
Azure Synapse is still new, and there are so many options, such as on-demand SQL and pausing pools, it is hard to say what the optimal solution is. However the more I think about it, the more I am convinced Azure Synapse is something you should take a close look at.
If your ADLS is Gen2, as opposed to Gen1, then you can ingest directly from the Storage Account instead of going thru the Managed Instance.