There are earplugs that minimize certain frequencies, e. g. Flare Calmer [1]. They have a report with frequency response graphs [2].
No idea if this helps with tinnitus at all.
[1] https://www.flareaudio.com/en-eu/collections/calmer [2] https://cdn.shopify.com/s/files/1/1721/0649/files/ISVR_Offic...