There are various stem and handle bar options out there. Do you know what stem/steerer design/size the bike uses? The 7500 model spanned a few years and the specs did evolve some over the span.

have you had an experienced fitter take a look at your position, as you pedal, and talk options for changes? One aspect of sitting more upright is that as your legs and torso angle opens up the power you can apply reduces. This is one reason why well designed upright bar bikes often have a slacker seat tube angle so one's butt can sit a bit further back, behind one's feet. This more rearward sit point position will increase core body muscles ability to support the upper body, reducing the weight on one's hands. Sadly when a "performance bike" has flat/upright bars it often still places the rider's sit point forward. Whether this is acceptable by the rider is for the test rides to discover.

When doing this "fitting" stuff on one's own it's often that the rider will end up wanting to try more than one solution, not knowing which path or dimension(s) work better for them and which would likely be a dead end. For those riders who enjoy this kind of process, make a change and ride the bike some to judge the results. And repeat till the results get worse then go back to a previous set up. I say great and you'll end up learning a lot about your needs, in time. But for those who don't want to end up with two or three extra stems or handle bars, stem risers that didn't result in what the rider thought would be the case and likely a few seats too I suggest finding a fitting shop.

While the cost for a fitting might not be a whole lot different then all those stems and such the rider had to buy to find out what was best the time spent getting to that point should be a lot quicker. Plus a good fitter will offer far more insight and advise than just what angle your arms need to be at, as a fit only example. I've watched my boss do his fittings for nearly 15 years now and am still disappointed in how little most riders know about how to ride their bikes. Most of his clients are as glad to learn about how to ride easier (even the simple "how to start pedaling from a stop") as they are for the actual fitting changes.

Generally flat/upright bars are measured from end to end, any rise from the clamping center to the grip portion, any angle back of that grip portion and the center clamping diameter. Stems have their rise and run (angle of the extension and how long it is C-C. Various "rules of thumb" exist for matching these dimensions to any one rider. Generally one starts by measuring their bars and stem to understand where they "are" currently and to begin to familiarize one's self with this stuff. Has the OP measured theirs yet? Andy