I manage it with these earplugs:
https://www.amazon.com/gp/product/B0051U7W32
I sleep in them, mostly so noises like the furnace coming on or the cats getting rowdy outside my bedroom don't wake me up. But also wear them anytime the tinnitus is bothering me. Things like road noise while driving, fan noise, vacuum cleaners, etc seem to aggravate mine, and the earplugs generally help lower the high-frequency noise in our environment. I've gotten so used to them that sometimes I don't realize they're in my ears. For me, it seems the less noise I have to process, the less tinnitus bothers me. So I've never used things like noise generators to mask the high-pitched ringing.
I cut about 1/4" off the tip of these earplugs before using them. If I don't, they puff out in my ear and will make it sore if worn for long periods of time. I wash them with soap and water and use them for months at a time, so that one jar of plugs has lasted me almost 10 years.