Wouldnt you just recompile your duckdb with the hacked Arrow?
You don't have to solve the entire world, you only need to hack what you actually use. If the issue with an optimized arrow impl is memory incompat in duckdb, recompile duckdb with your hacked arrow. This is where "overengineered" stuff like mono repos really shine. I've done exactly this type of thing at past jobs.
Don't let perfect be the enemy of good enough.