Components that are not used, that almost always get replaced by vendors do not get much love. That the base AOSP should be optimized to use out of the box is a purist fantasy. In reality AOSP is made with the understanding that vendors are going to customize it. A lot of Android is designed to be modular, you can easily install a different keyboard app.
CJK languages need language-specific AI conversion engines for any kind of typing. Which OSS versions exist for Japanese, I don't know for Chineses(CN/HK/TW - IIUC they're slightly divergent beyond fonts).
I would immediately jump ship if I could buy a phone that supports a truly free OS. Instead, I'm stuck with an option between a reasonably-secure, but completely locked-down phone (both hardware and software) with an exorbitant life-long cost and semi-locked-down phones with a pseudo-FOSS OS, whose main business is to my leak personal data for a dozen companies. Honestly, the only reason why Android (and iOS) reign unchallenged is because of their iron grip over the hardware ecosystem.
> I would immediately jump ship if I could buy a phone that supports a truly free OS.
Is your definition of “Phone” equivalent to “must run apps (non-emulated) for iPhone and/or Android”? Otherwise, I mean, these things do exist: <https://puri.sm/products/librem-5/>
My definition of a phone platform is that a reasonable app ecosystem must exist. Or at least the ability to easily develop the ones I need - I don't mind developing for my needs. If a more secure phone without a substantial app ecosystem is enough, then a feature phone would be fine. Librem phone unfortunately doesn't meet that requirement.
The difficulty is that even many essential service APIs are not open to alternative implementations.
Its value and main goal is to suffocate any initiative on mobile space, call it immense if you will, but I concede it certainly works.