I
HATE how most ear plugs kill the fidelity, but I think it's another occurrence of Fletcher-Munsen jumping in there and screwing with us; Even with plugs that claim there's no loss of fidelity, simply reducing the sound level is going to change what our brain perceives.
With that in mind I searched for a couple years and eventually found that
ASI Audio makes a really interesting IEM set that has mics in each ear that feed a little belt pack amplifier. We can adjust the volume of that amplifier, its built-in limiter, and the EQ. And, the adjustments can be set individually for either ear, or joined so the controls act on both at once. The pack can also take a feed from a regular IEM receiver and that can be blended into the ambient sound the built-in mics capture. They're expensive though, $799. I think they're a good product but definitely not in most people's budget. They fit into mine because of frustration and really wanting to take care of my hearing - I have multiple octaves of tinnitus firing into my head continuously and don't want more.
Because of the tinnitus I joined a hearing study that Apple is doing with some universities IIRC. The
AirPods Pro 2 have noise canceling, and using that feature along with some other technologies built into the AirPods, they added a mode that makes them act like active ear plugs so they'll clamp down on transients. I've used them a couple times when playing and that part worked well. I wasn't thrilled with the frequency response I was hearing but haven't dug into them to see if I can set a custom response. Overall though I think they're worth investigating because they're half the cost of the ASI Audio unit. IMO, the only reason to spend the money for the ASI units is when someone needs to incorporate a FOH IEM feed. Apple's AirPod Pro over-the-ear headphones will do it too, and probably keep out more ambient sound, but they're up there in price with the ASI Audio unit.