These boutique pieces of tech are bound to fail because they don't stand upon the shoulders of giants. We see it everywhere in the phone world: phones aimed at

These boutique pieces of tech are bound to fail because they don't stand upon the shoulders of giants. We see it everywhere in the phone world: phones aimed at the elderly have buggy horrible software and become quickly abandoned; modern feature phones are buggy, slow and incomplete because nobody in their right mind assigns their best engineers to the dumb phone division, not Nokia, not LG; plus small companies like Mudita, Punkt, Light and others don't have the know how to produce a complete device. The only real solution is the true "hacker path"of taking existing perfected and mass produced technology and achieve your goal with a few small modifications. If your goal is to have a basically "dumb" experience, why aren't you getting a bunch of 5yo Xiaomi phones, follow the extremely safe guides and flash LineageOS without Google Services on them? And maybe pair them with a SIM card with no data? This way you get a snappy phone with actually usable offline applications (and you can sideload the ones you truly need).