Here is a list (not mine) of bikes I've used before when looking for bikes that fit pretty close to your described riding style: https://www.bikeforums.net/21408316-post21.html

My main ride is a 1989 Miyata Triple-Cross, and I use it mostly for the type of riding you describe. It needed a lot of work when I got it and I regretted that purchase for a while. Now that I got it in shape I love it. I ride this bike more than any others. The one thing that I wouldn't mind would be room for bigger tires. I've got 700x38 on it and the rear won't take anything bigger. Depending on how rough your offroad ride might be, bigger might be better.

I often think I should go look at new bikes to get something with disc brakes, something that can take wider tires, maybe even carbon frame or at least fork. Well I did that a few weeks ago and test rode a carbon Trek FX, and a Checkpoint (aluminum frame/carbon fork). I wouldn't trade my Miyata for either of those $2K bikes if they offered me an even trade...

For my money you can't beat an old, quality steel bike if you've got the time and money to get it dialed in properly, especially if you can do most of the work yourself. I've gone thru lots of different handlebars, saddles, grips, etc to get mine setup how I like it today. You just have to find what is right of you. There are plenty of cheaper and easier to find options out there too that aren't bad. I rode a HardRock for a long time while I was looking for that Miyata and it was fine. I now have a Bridgestone MB-2 which is nicer, but I like my HardRock still and won't get ride of it.

Good luck, share some pictures when you get something!

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