Use a clickhouse FDW or something similar, clickhouse has excellent integration with postgres. They also have a great embedded Python version. Their marketing isn't as good as Duckdb but in terms of stability and performance they are so much better. Duckdb is very very buggy and full of sharp edges but because of their VC funded developer marketing, you don't really hear people talking about it.
Why are you painting Clickhouse as an underdog, with no VC funding? They raised a $250M Series B.
I agree that DuckDB may sometimes be buggy because it's being actively developed with a large surface area (a universal embeddable query engine that works with different storage layers if I were to simplify).
However, DuckDB (non-profit foundation) != MotherDuck (VC funded). These are two separate organizations with different goals. I see DuckDB as a tool, not as a SaaS or a VC-funded company. My hope is that it'll be adopted by other projects and not associated with just a single for-profit company.