Sounds like you could get pretty much what you want int he used bike market right now. Just gotta figure out exactly what it is you actually want.
Sounds like a gravel bike, or even a touring bike (LHT, 520 or Marakesh type new steel touring bike) would all work, but your not so big a that you couldn't look at some carbon bikes.
I would go to eBay and do some window shopping, just put in your size and cap the amount you want to spend (don't forget shipping) and see if anything pops up that really gets your attention. You'll prolly know it when you see it.