We've had issues with the modifier search in the new item library too. It seems like the search in the modifier picker doesn't work the same way as the old version — partial matches and name-based searches seem broken.
What's worked for us:
1. Try searching by the exact modifier set name rather than individual modifier names
2. Scroll the list — if you only have a handful of modifier sets, scrolling might be faster than searching until they fix it
3. Create the item first, then add modifiers from the item edit screen rather than during creation — sometimes the search works better there
This feels like a bug in the new UI rather than intended behaviour. The old item creation flow had a working modifier search. If you haven't already, I'd post this in the Feedback section too — the more people flag it, the faster it gets fixed.
