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As you move through the world, hearing is a particularily handy trait. It allows you to hear approaching traffic, know if people are around you, allows you to commmunicate and if you are a soldier you'll be able to hear danger and get an approximate location. Modern day soldiers also carry a lot of hearing protection to prevent lasting damage. So if the hearing protection is pretty much mandatory it would be better to build it as standard in super-soldiers. The goal is that these solutions are growable, maintainable and repairable by the biological body of the soldier in question.
My own idea's:
Localization: Ears can localize a sound, but Human ears for example have their limits. If a sound is coming from directly in front or behind you, it becomes almost impossible for your brain to tell if the sound is either in front or behind you. Barn Owls (https://www.barnowltrust.org.uk/owl-facts-for-kids/barn-owl-hearing/) use ears that aren't symetrically placed on the head to counter this, not only are they asymetrically placed on the vertical plane, but also on the horizontal plane allowing them to pinpoint a rodent under the snow better. Perhaps there is also room for another set or (rudimentary?) ears on the body for both redundancy and better localization. Or maybe just place 2 earholes per ear if that works.
Hearing protection: I have little idea how to protect the ears continuously without impairing the hearing. Preferably whatever protection is used should automatically kick in when a soundwave/pressurewave reaches a certain threshold to protect the ear. Or perhaps the vulnerable parts of the ear that get damaged could be replaced with something sturdier. A build-in hearing protection like those musicians use which filter out/reduce lots of sounds above a certain threshold seems like a pretty good start but it won't be enough for a battlefield.