Im looking into an FPV system/plane signal that can fly for lengthy periods
Meaning a rc plane/transmitter system that I can control FPV through goggles, and the plan can fly for 1-2 miles without losing signal. How do I find a transmitter/FPV system with those strengths /capabilities?
Don't know but is worth checking on they may have better system , I posted to give some idea what can be done , a pointer to start the search with.... found this so looks like they are still trading
ELRS (express LRS) I think is the best option right now for the radio control and telemetry data. There's a wide range of actual hardware that runs ELRS firmware for the radio link so can get higher powered or lower frequency/longer wavelength radios and can basically make a trade off in the refresh rate and the quality of the signals. ELRS is based on LoRa (long range) radio technology basically developed for low power long range radio transmission for things like weather beacons/sensors used for research purposes and the like.
ExpressLRS aims to provide the best completely open, high refresh radio control link while maintaining a maximum achievable range at that rate with low latency. Vast support of hardware in both 900 MHz and 2.4 GHz frequencies.
www.expresslrs.org
For the vid signal the main thing is having clear line of sight between you and the craft, but I want to say analog systems are still probably the better option for any sort of long range flights since digital is an "all or nothing" deal typically... either you have very nice looking video or you have no video, whereas analog is more of a noticeable progressive fall off of signal and can at least show some signal through all the noise when it's very weak whereas digital just locks up or goes to black once it gets a signal it can't properly decode.
Also for most long range things I've seen folks are using polarized/directional antenna (or combo of directional and omni in some cases).
Regarding GPS you can get a BN880 module that has a GPS receiver and compass built into one package and works fairly well from some basic testing I've done with them but can't say I've every even attempted any real long range flights since I live in a pretty densely populated area and haven't really brought my quadcopter on vacations anywhere that would allow for long range it hasn't ever come up for me.
With regard to the DJI NAZA stuff from any links I can find it looks like it's basically "legacy support" at this point and/or not available in my region (US) https://store.dji.com/product/naza-m-lite?site=brandsite&from=insite_search they all link back to the www-v1 subdomain so think is just legacy/archived copy of the site before redesign. That is basically one of my beefs with proprietary systems/reasons to just go open source stuff, companies just decide at some point a product is no longer worth supporting and just cut them out entirely. Open source things are effectively immortal (people might stop working on a project/updating it but can always get copies of the old versions that worked and/or find someone with the skill and pay them to update it to work with whatever).
On topic of GPS flight I also have only really dabbled with using iNav for some kind of autonomous control but very very limited experience with that (just got it setup and did a few test take off and hovers, and needed a lot of tuning for a scary hexacopter I built ). Betaflight only uses the GPS for "failsafe recovery" no waypoint planner or anything, it just comes into play if you lose signals for longer than the timeout and failsafe kicks in then it will try to go up above the highest altitude you flew during the flight and b-line it back to the home/take-off position (you need to give it a minute on the ground before take off to acquire GPS or else the return to home will not work).