@Robert Garcia yeah this is exactly the right question to ask before committing to an antenna setup, and honestly good on you for being skeptical upfront — most people don't ask until after they've torched their link budget.
The RF front-end on the MultiNav Pro+ is designed with a 50 ohm output, so a direct connection to a 50 ohm antenna like a yagi is what you want and you shouldn't need external matching as long as your feedline and connector are reasonably clean. The matching network is already on the module, which is part of how they're hitting those sensitivity numbers without expecting you to do RF voodoo on your end. That said, if you're using any length of coax between the module and the yagi, keep an eye on your connector quality — at 2.4GHz even a mediocre SMA joint will eat into your margin more than you'd expect.
For your actual use case — 5-10km semi-rural with a couple obstacles — honestly that sounds very achievable. The 50km figure is drone-to-drone with both units elevated and no ground reflection garbage to deal with. Ground-to-ground is rated at 5km, but that assumes omnidirectional antennas on both ends. If you're running a yagi on the moving asset side pointed at a fixed base, you're adding directional gain into the link budget which should more than compensate for a few soft obstacles like vegetation or rolling terrain. You're essentially working in the middle of the performance envelope with a configuration that's better than the ground-to-ground baseline, so I'd be surprised if 5-10km gave you trouble.
For deeper integration docs, your best bet is to head into the RFOXiA Club resources section — the hardware integration guides there go further than the public datasheet. If you're not already in the Club it's free to sign up and there's actual SDK and technical documentation in there that doesn't live anywhere else. Would also be worth posting your specific deployment geometry there because Moamen (the founder) does engage directly on technical threads and he's the one who actually designed the RF front-end, so you'd be getting the answer straight from the source.
