You have stumbled upon Matt's brain dump. I am a big data engineer by trait, but like to experiment with other programming languages.
Currently, I'm exploring data lakehouse formats such as Iceberg and Delta Lake; I also like to use simple data processing tools like polars an duckdb. Spark is great and all, but sometimes you don't need a sledgehammer to crack a peanut
My first major project was called "SQL ETL". It would from T-SQL assemble and create an SSIS package on the fly. That repo can be found here.