Get a bigger hat. :)
You know those “custom molded” earplug that specialists charge you a ton of money for? You can make them yourself. Pretty much the same thing, for about $12-15 a set. Look for the do-it-yourself kits.
I wear them for 6+ hours at a time and forget they are on.
Put some electronic muffs like Leight or Peltor on over them with the volume turned up. Comfortable and you can still hear a little bit.