I also have serious hearing loss and tinnitus (drives me nuts). I arrived at my current handgun ammo selection by comparing .45ACP, supersonic 9mm, and subsonic 9mm while shooting at an indoor range. For me they rate in the order I listed them from loudest down. So I shoot subsonic 9mm exclusively. The sonic crack of lighter 9mm rounds is louder, and the boom of the .45 is louder still. So the supersonic crack is a factor, but for me it's certainly not the only factor.
For earpro I always double up when shooting indoors. The muffs I use are Peltor ProTac with the optional gel seals. Quite comfortable, and they are available in 21dB and 25dB NRR versions. The 21dB NRR model is great for outdoor shooting and I can wear either of them all day with no discomfort. I also keep a pair by each gun located in my house. I use the 25dB NRR model for indoor shooting (over plugs) or if I attend a class.
The only rifle I have left is a suppressed 300 BLK bolt gun. So far I only shoot supersonic ammo. It is probably the most quiet center fire long gun I can think of, other than using subsonics.
If I had protected my ears when I was younger my life would be much more pleasant now, and being a shooter would be more enjoyable.