Generally speaking, the best solution to most problems is at the source. Hence my preference for airguns, as they are for the most part hearing safe, at least the lower power versions. I doubt I'll ever get into necked cartridges simply because even with hearing protection I'm simply too sensitive to noise, always have been. On the plus side, my sensitive hearing is an advantage for my work. Accurately perceiving sound us crucial in doing work for musicians, setting up their instruments to produce optimum sound qualities. The violin family make for some subtle acoustical needs. But I happen to like shooting. So I stick to the lower power things; airguns, .22lr, and 9mm. That way a single layer of earpro is sufficient. I have some custom fitted active Etymotics as well as matching silicone plugs for when the batteries die.
But to my initial point regarding the noise source, it seems the Brits and many other European/Scandinavian countries have that figured out, along with South Africa, New Zealand, and I think 37 of the US states. Suppressors, legal and for the most part cheap in these places (the USA a notable exception with their NFA causing jacked up pricing), take noise down to hearing safe levels for most firearms, and for the most powerful firearms at least to single level earpro volume. But I guess hearing protection of the most effective sort is too spooky for Canadian lawyers and politicians...