There does seem to be some degree of variety. There's Android, including de-Googled Android. KaiOS, based on Android Open Source Programme (AOSP) and the form

There does seem to be some degree of variety. There's Android, including de-Googled Android. KaiOS, based on Android Open Source Programme (AOSP) and the former Firefox OS usually further simplified. May or may not include crapware on devices. <https://en.wikipedia.org/wiki/KaiOS https://en.wikipedia.org/wiki/KaiOS>. GrapheneOS, also based on AOSP, but fully Open Source: <https://en.wikipedia.org/wiki/GrapheneOS https://en.wikipedia.org/wiki/GrapheneOS>. LightOS, used on Lite Phone, is an Android fork. <https://en.wikipedia.org/wiki/LightOS https://en.wikipedia.org/wiki/LightOS> Series 30+ OS (S30+), an Nokia / HMD branded mobile OS based on earlier Nokia operating systems, confusingly Series 30 (2001--2014) and Series 40 (2002--2014). Systems are preloaded with the Opera browser and Facebook app. (Latter is a dealbreaker for me.) <https://en.wikipedia.org/wiki/Series_30%2B https://en.wikipedia.org/wiki/Series_30%2B>. Linux: Used by Pinephone (as SailfishOS) and Purism (as PureOS). <https://en.wikipedia.org/wiki/Sailfish_OS https://en.wikipedia.org/wiki/Sailfish_OS> <https://en.wikipedia.org/wiki/PureOS https://en.wikipedia.org/wiki/PureOS>. For those looking for a minimised attack surface, this is disheartening. I'm ... torn by multiple apathies. - Many of the phones are expensive particularly for specs. Given low production volumes, sales friction, and lack of co-branding / data mining, this is somewhat understandable. - For those seeking privacy and distraction-free experiences, devices are often compromised in frustrating ways. I'd prefer a monochrome display, for example, and highly robust call-screening / curtailing features (there are very few people who should be able to contact me). I don't want social media and app preloads, outside a very limited set. - Devices often have frustrating technical limitations. The Punkt mp02 for example, fails to support most North American mobile networks. Punkt's most recent release is far more a full-featured smartphone, which suggests an abandonment of the firm's earlier ethos. - Phones with features I find more appealing are often straight out of China, which raises its own host of concerns. Of course, pretty much all phones are built in China, or source Chinese-made parts, so that may well be a moot point. Even given that, compatibility of those devices with other country's mobile networks is a concern. On call management: I'm pretty convinced I don't want to be be generally reachable by World+Dog, and expect to have quite robust features for limiting / rejecting calls. Ultimately this might best be done by having a full-featured VOIP relay which is my primary number, with select calls forwarded to my mobile. The latter would only accept calls from the first system. The VOIP system would have its own ruleset for accepting, rejecting, directing to voicemail/messaging, or in very rare cases, forwarding, calls. Pretty much all other smartphone features I'd prefer accessing on a small-form-factor, flexible, full-function laptop. Framework Laptop 12 seems to be the best choice for this. For dedicated image / video / audio capture, dedicated devices. I've had an e-book reader and find that this, dedicated to that and directly-related tasks alone is preferable to a smartphone. I still have many frustrations with extant e-book reader offerings (most fail abysmally at organising a significant library), but that's another story. HN has quite a trove of submissions on the dumbphone phenomenenon (<https://hn.algolia.com/?dateRange=all&page=0&prefix=false&query=dumbphone&sort=byPopularity&type=story https://hn.algolia.com/?dateRange=all&page=0&prefix=false&qu...>), dating back fourteen years: "The dumbphone strikes back" (2012) <https://news.ycombinator.com/item?id=3533120 https://news.ycombinator.com/item?id=3533120>. Interestingly, the first comment on that thread reflects my philosophy stated above: <https://news.ycombinator.com/item?id=3533428 https://news.ycombinator.com/item?id=3533428>. A 2019 "best dumbphone" submission has a number of suggestions, few of which have changed much: <https://news.ycombinator.com/item?id=19423434 https://news.ycombinator.com/item?id=19423434>. There's a Dumbphone Finder: <https://josebriones.org/dumbphone-finder https://josebriones.org/dumbphone-finder>, though I can't get the page to work.... And whilst I strongly avoid Reddit these days, there is an /r/dumbphone sub.