I’d like to get away from phones with a backlight, at least for my next non-smartphone.
FYI, Passive Matrix doesn’t mean monochrome. Passive Matrix were color too. If you’re actually looking for a reflective monochrome LCD, you probably want STN aka Supertwist LCD.
I’m not aware of any STN smartphones. Others have already rightly posted eink is likely a better fit for what you want.
There are eink phones.
TCL make those NXTpaper phones, but I have no idea if they’re any good.
Nowadays your best bet is e-ink, I think I’ve heard of a few examples, but they’re rather expensive for the specs you get
They are also very Chinese and closed and without a proper Google Play store. I used a HiSense 5c pro as daily phone (hope I have the name right).
Bought it because I’m quite interested in eink. It is interesting to use and it is really usable. It is ok to read text on. I was not able to root it and was thus a bit locked in. The lock screen couldn’t be adapted to my liking and I did not fully trust in what spying it might be doing (like Google location tracking and such).
Interesting, do you browse Lemmy on it? How is the experience?