@Douglas Young ground plane actually matters more than people expect, even with a high-sensitivity front-end — maybe especially with one. The reason is that a fragmented or poorly stitched ground raises the noise floor, and when you're operating at the edge of receiver sensitivity (which is exactly where you're living at 50km drone-to-drone), even a 2-3 dB hit can cut your practical range noticeably. The module is doing a lot of heavy lifting on the RF side, but it can't compensate for a bad reference plane underneath it.
That said, "obsessing" probably isn't the right frame. The basics will get you 95% of the way there: solid unbroken copper pour under and around the module, stitching vias around the perimeter to tie layers together, and keeping any signals that don't need to be near the antenna away from that region. Where people actually lose range is usually running traces under the RF section or splitting the ground plane with a slot from a power domain — those are the real killers, not minor imperfections in fill coverage.
If you share what your stack-up looks like I can probably give you a more specific read on whether what you're doing is fine or worth revisiting.
