"Expression.Error: A cyclic reference was encountered during evaluation." After Remove Row Datasourc

I would suggest that many of these issues are coming from a really extensive query that appears to have many identical steps. Combining those steps and then looking at the advanced editor for references to the columns that you deleted should make a huge difference, both in query performance and in diagnosing issues. For example, I'm seeing a ton of joins followed by removing columns and then renaming them. Without importing the prefixes, could you correct the columns to what you need in the source table and then when you expand, only bring over the columns needed? I would also suggest looking at solving some of those joins through schema to save on query time.

Start by streamlining the query and expanding the schema, and then check for column references inside of the advanced editor.