Recycler productivity research tech increases the amount of items returned by recyclers. At level 30 recyclers return 100% of item ingredients (which is a hard cap). Hence suggestion for this mod: at Recycler productivity research level 10 (which is +100%, which results in 50% items returned) - change the recipes (or unlock a better tier of Deterministic Recyclers) to return 2x ingredients from 4x items. Similar for Recycler productivity research level 20 (+200%, resulting in 75% return) - 3x ingredients from 4x items.

In Vanilla the Recycler Productivity only affects the Scrap recycling. So this wasn't really in scope of the project. Furthermore I don't think it is possible to dynamically adjust recipes to the productivity research level. Recipes at 100%, 200% and 300% productivity are nice, but when you get to 170% productivity. I would need to give 27x ingredients from 40x items to avoid fractions. I don't think many want that behaviour either. I rather let the game handle the productivity itself. It's possible though that this mod is not yet compatible with the mod you're using to give the recycling recipes productivity. So please tell me which mod that is so I can take a look at it.