T-SQL How to retrieve metadata from SQL proc containing temp tables

I've a T-SQL stored proc running in a Microsoft SQL Server 2019 environment. The proc contains temp tables, dynamic SQL and is 2000+ lines. The proc's output has been verified and tested for completeness and accuracy; re-writing the proc is not an option. Attempts using sp_describe_first_result_set and OPENROWSET to retrieve metadata have failed due to the use of temp tables and dynamic SQL. Research links used: and this. Are there any other approaches to retrieve metadata? Thoughts?