Well for a 6 month old you'll need the wedge in the Joie, which does make it quite reclined still, similar to an infant carrier. She'll be higher up, but not a huge amount more upright. Perhaps 10 degrees or so.
Once you can remove the wedge (somewhere around 12 months, though does depend on the child's build) it is fairly upright, but not as upright as something like the Axkid Minikid, and not as upright as e.g. a forward facing Group 1 seat unless you have very angled rear seats.
They go more upright than the Joie Stages/Graco Extend etc type seats which can only be used in recline mode rear facing.
You could look at spin seats which don't have a wedge, like Britax Dualfix.
Like all isofix seats, the actual angle you'll get is also dependent on the angle of the isofix in the back of your car. If your car has quite tilted back seats and low down isofix points, then a RF spin seat will be pretty upright. If your car has quite flat back seats, or raised isofix points to counter the slope then a RF spin seat will be quite reclined, even when it's on the most upright setting (if that makes sense?) So in actual fact it might be best to just go to your nearest large baby store or rear facing specialist and physically try some seats out in the car.
I know what you mean because I also wanted the seats to be more upright for the second stage, everyone seemed to be interested in the recline and I wanted the opposite! There is also a big wedge built into the base of a lot of spinning seats which makes them seem very upright in forward facing mode and very reclined in RF mode. There are two reasons for this, one of them is that most car back seats have a slope so it helps to cancel that out, but also the rear facing mode is often approved for younger babies under 3/4 months and therefore you need a certain amount of recline to support their lack of neck control.
I've added a collage pic showing the Joie 360 (blue seat, white t-shirt) on both the most reclined and most upright settings, this is with the wedge and body insert in, DS3 was around 12/13 months in this photo. Without the wedge it's a bit more upright but I don't have a great photo - just this one of my older DS2 (tongue sticking out).
Compare to the promo picture of Axkid of their Minikid seat (black seat, little girl pink clothes) which is quite a bit more upright.