Not the parent poster, but I wouldn't race to solve the problem via supporting many more connectors that require lots of config options. You'll just spend time supporting lots of connectors.

Instead, recommend that users use another (connector heavy) tool to get data in -- my mind jumped to using Benthos to convert a CSV or parquet file (or any other input stream) into a series of JSON calls -- and just ask users to hammer ingestion requests at your server. From there, your job is "just" to handle JSON ingestion as fast as you can, rather than maintain many connectors.

If JSON becomes a problem, then find exactly one other well-defined file format for bulk data loads (parquet, perhaps?), and support that.

When I saw this submission, I think I fell in love. JSON to get data in; SQL to get data out; what could be simpler?