Ah, glad it's not just me! My hearing is generally OK - left ear has better hearing than the right and has been since my 20's - but my left "clips" like a cheap speaker being driven too hard at high volumes. I suspect that 2 bits that are supposed to be stuck to each other are simply resting against each other which works at low volumes but less so at high volumes. NHS has determined that my hearing at low volumes is fine, and that seems to be the limit of their tests, though I'm not sure that there's anything they could do to fix the inner ear when earplugs help and don't cost the NHS anything..
Which gets me to earplugs, which I carry with me constantly and use a lot. The key things I've learnt is that plugs must fit well and be comfortable. Sound obvious but isn't necessarily easy to achieve.
I tried an expensive set of moulded plugs that were great as long as I held my jaw in exactly the same position as it was in when the plugs were made. Not good. Held on to them for a while but eventually gave in and consigned them to the bin.
I bought a box of mixed foam plugs to try after that https://www.deltawaite.co.uk/product...plug-Selection
Many people struggle with foam plugs as they don't put them in right; with a really good squeeze and quick insertion with a pulled back ear lobe they go right into the ear canal and expand in just the right place. For regular use, I've come to love the MaxLite plugs (34dB SNR) as they are ridiculously comfortable and for louder environments the slightly less comfortable but slightly quieter LaserLite (35dB SNR)
Like others here, I've tried Flare audio and have both Isolate Pro Titanium and Isolate Pro Mini Titanium plugs. I think the advertising for these is somewhat over the top. They work OK with careful positioning in the ear, but I find them uncomfortable to use for any period of time. Great for popping in and out in the office but not on a ride on the bike. I do carry them in my pocket all the time, though I also have MaxLites in the same bag and if I'm doing anything that isn't going to require me to take them out to talk to people, I use the MaxLites.
For motorcycle use, I'd seriously recommend getting a pick-n-mix selection, finding which suits you and learning to put them in correctly. They are quiet, comfortable and adapt to the shape of your ear as you move. And they're dirt cheap by comparison.
https://www.deltawaite.co.uk/product...plug-Selection