Hi I used to cycle quite a lot and about 26 years ago bought a men's trek singletrack 970 which I loved. That eventually got stolen, and I haven't ridden for many years, but when I tried out some bikes at the beginning of the year they all felt like I was sitting upright which just felt wrong!
You should seriously consider drop bars.
Drop bars have two major benefits over straight handlebars.
Firstly, drop bars are designed for an aerodynamic position where part of your weight is supported by your arms. This is the opposite of an upright position typical on most straight bar bikes.
Secondly, because on very long rides your arms will become tired if you stay continuously in the most aerodynamic position possible, drop bars offer many other positions too. You can keep your hands in the drops, in the hoods, in the corners and on the short straight section of the bar. Thus, a drop bar bike allows at least four different positions some of which are more upright than others and some of which are more aerodynamic than others.
Don't believe the people that tell you that drop bars are not suitable for anything except smooth pavement. You can perfectly well ride a drop bar bike in a forest trail. If riding outside smooth pavement often, just put some wide tires with a non-slick tread pattern. Cyclocross is just like that; riding a drop bar bike outside of smooth pavement.
Heck, you can even have drop bars on a bike having suspension fork! (I had such a bike after converting a straight bar bike with a suspension fork to drop bars.) However, you probably will find that drop bars allow you to easily use your arms as suspension, so with drop bars a suspension fork is not a necessity like it may be with straight bars. So, for example cyclocross bikes do not have suspension forks whereas many mountain bikes do.