Have you tried noise cancelling headphones? I know several people with sensory overload problems and they tell me noise cancelling headphones are transformative.
I like earplugs too, but again that can look look rude in social situations. My girlfriend and close friends get it, but it depends on who I'm with what I'm doing.
I think Airpods might be changing things though, it's quite common to see people with those in 24/7. I haven't tried them myself, but I've heard really good things about their transparency mode.
I have tried suppressing sound with more sound over the years but that is not even 20% as efficient (for me). Now may recipe for relaxation is EarPods in, Noice canceling on, a song on repeat and Bob's your uncle! Better than retalin even.