Universal Music Book Stand - Sheet Music Stand Fits 61-Key 88-Key Digital Piano Keyboards With a Slot ≥48cm/18.9in Length, Max Inner Gap (If dual-slot) ≤38cm/14.96in | Not for Round Jacks

You can contact yamaha here https://usa.yamaha.com/support/contacts/index.html but I doubt they have any. This rest looks similar, maybe it works? https://www.amazon.com/Yamaha-YMR-03-Music-Rest-CP300/dp/B01D1U97FY/ref=sr_1_1 If your piano has slots this one at Amazon looks great and might even look like original: https://www.amazon.com/ATNEDCVH-keyboard-compatible-digital-keyboards/dp/B09GKB8YQP/ref=sr_1_2