$30 fiber meter
https://www.amazon.com/gp/product/B07XKH68B3/ref=sw_img_1?smid=A1GPQOUQCUBXWP&th=1
This one has 705 4 star reviews, what do you think? It's the highest rated one on Amazon.
Do you have a light meter to measure the output? If it is saying -22 that is likely a failed SFP.
Worth 30 bucks for sure - https://www.amazon.com/YEDEMC-Portable-Optical-universal-interface/dp/B07XKH68B3