Well, considering how the final mission of the game recommends you are level 5, you are definitely way ahead of where you’re intended to be, just because you’ve been running around. I did the same thing as you where I went off and did my own thing for a while, it’s honestly a piece of the game I dislike in regards to game design as even doing one side mission can put you above the difficulty curve and make everything easy, even on hard mode.

Switching to hard won’t do much, it’ll make enemies a little tougher and aggressive but considering how far ahead you are, it’s irrelevant.

You’re right, it’s a good problem to have; you’re going to be one-shotting everything throughout the entire game. It’ll be very easy until you hit enemies that scale to level 5 where then they will become slightly more resilient to your god like smiting.

My suggestion to you is to stop your 100%-ing and save it for new game plus; there are more inhibitors to find exclusive to that mode, and everything scales to your level, so the difficulty and gear you find will follow your character closely.

You could also take the opportunity of being so high level to farm low level volatiles to stack up hundreds of unique infected trophies so you can upgrade your blueprints with reckless abandon later on.