Perhaps the upside is that you have essentially received the same (or similar) information from two independent sources - of which one has no interest in persuading you to purchase a replacement device.
Accessories that incorporate Apple’s proprietary interface (this being licensed to third-party manufacturer’s on a royalty basis) cannot be readily used with other open/industry standard interfaces such as USB. Contrary to seemingly popular understanding, Lightning is not just a proprietary connector with which an appropriate cable can “adapt” the connection - but is entirely different in both electrical and signalling standards.
As for your external GPS receiver, while BadElf market solid and well respected GPS hardware solutions, there are many others from which to choose that offer USB or Bluetooth connection options.
Wired solutions are in some circumstances a better option - as Bluetooth, being reliant upon an RF-link, is susceptible to interference from adjacent devices; in some RF-cluttered environments, BT and BTLE radios may not even be useable.
Bluetooth does have some advantages - in particular where GPS signals are either shaded or blocked from the host device (GPS signals being primarily being line-of-sight). As examples, typical applications are marine and aviation environments, such as yours.