My other recommendation would be to consider a standing desk. Even if you prefer to use it sitting, you can tweak the desktop height to your liking and help mitigate the posture issue.
Back to the Jarvis, though: see how the photos of it show the arm in a typical "bent knee" shape? You can totally use it with both halves of the arm pointed in the same direction. I just did a quick measurement on mine and each of the arms is about 25 cm long, and they're fixed at a ~45° angle. So if you center its mount on your desk, you should be able to bring the monitor around[2] 35 cm closer to your face and still retain a lot of height adjustment (~34 to ~50, as measured from your desktop to the center of the display).
If you go this route (and your desk doesn't have an existing grommet hole you can use), they sell a drill bit to bore one in the right diameter.
[0]: https://store.hermanmiller.com/office-furniture-desk-accesso...
[1]: https://www.upliftdesk.com/desk-accessories/monitor-arms/
[2]: cos(45°)*50cm
I have the dual version of this, which they don't seem to sell any more: https://www.upliftdesk.com/crestview-single-monitor-arm-by-u... but if you look at the "all components" image, you can see the steel plates and bolts that I use to attach mine - the bolts aren't part of the bent black thing, they work with that or either of the shiny steel plates. Those both fit within a grommet hole (the large circular holes in desks) with bit of free movement to adjust it, and the bottom of the "stand" is completely flat so it could very easily go anywhere - you put the plate under the desk, stick the bolts through it + through the desk hole, and they go into threaded holes on the underside of the stand.
Some monitor arms are only meant to clamp onto the edge of a desk, and you won't be able to do this - I'd probably avoid those in this case tbh.
(I've probably failed to adequately describe it - I can take pictures or draw something out if you'd like. It's not complicated, it's just... there are not many similar things that I can point to as a comparison that most people have at hand)
I use this one myself: https://www.amazon.com/gp/aw/d/B00B21TLQU
It can go far taller than I need it to, and the length of the arm itself should be enough that, positioned well, I imagine you could get it situated however you wanted.
Off the top of my head, I know I've seen this for Knoll Sapper, which the PDF brochure (linked below) says has posts up to 32" high. Not sure if the 17" horizontal extension is enough for you, though you could also drill a hole in a desk and mount the post further forward instead of clamping on the back. Or heck, clamp it on the side or front.
See page 7 here: https://www.knoll.com/document/1352941326370/Copy%20of%20Sap...
