Yes please for this. The chipsets for the GS290 and GX290 look identical on the website so my guess is it would be fairly straightforward to adapt it, but I suppose that is easy for an outsider to say.
I can imagine that there is a lot of crossover between the people seeking privacy and escape from big tech and outdoor adventure seekers. The GX290 is not only rugged but has a huge battery which would suit someone camping who might still want some connection or maybe just GPS and phone for emergencies.
Can I also suggest Unihertz phones (also based on MediaTek chipsets). They have small phones which suit people wanting to escape smartphone addiction (one reviewer helpfully said ‘you won’t want to use it and that is the point’ ). They have a rugged line, the Atom and the Atom L/XL models. But also very small phone non-rugged phones like the Jelly/Jelly Pro/Jelly 2. These are a lot cheaper than the rugged/waterproof versions and a backpacker will probably already have a drybag for money, passport etc. Keep up the good work.