Look for a product called "sound deadening duct liner" or "acoustic duct liner". Both are about 1" thick and meant to control vibrations traveling inside the duct. Adding mass loaded vinyl and securing the duct better will help with sound traveling in the duct metal. These people sell a lot of good choices - https://www.soundproofcow.com/soundproofing-101/how-to-soundproof-a-home-2/how-to-soundproof-hvac-systems/

I personally would avoid the open fiberglass duct board. It was (maybe is) widely used for a long time, but the fiberglass material is exposed on the inside and you invariably have to be introducing some fiberglass fibers into air circulation. There is no good way to clean it because it is friable and porous, and any vigorous rubbing will just release a bunch of fiberglass into your house...