While still a “sister”/subsidiary company, Huami’s Amazfit Bip (particularly the 1st gen but I think also the Bip S IIRC) have transflective memory-in-pixel screens with 1-3 months of battery life (3 months being almost an anomaly that I experienced with a fresh battery) - while still tracking movement and sleep.
I got an Amazfit Band 7 after my OG Bip died. More info as far as blood o2 and fitness recovery & VO2 estimates etc, but it loses the compass, barometer, a physical button (bizarrely imo) & a few month(s) of battery life. The OLED is certainly nicer in some situations (almost always indoors) but I very much miss the battery life. Oh, and lots of app & custom watchface support too.
Btw if you have a larger budget, Garmin is also apparently pretty good with good battery life and a very similar screen type (and much better sports tracking).
Transflective LCD, e-paper or similar always visible low-power display technology is mandatory for infrequently charged compact wearables.
I tried I like Amazfit Bip (older, more contrast, low refresh frequency) and Amazfit Bip S (newer, less contrast, higher refresh frequency, music playback control) devices that work for more than a month on one charge. For Android synchronization one can use excellent FOSS Gadgetbridge app.
I got an Amazfit Band 7 after my OG Bip died. More info as far as blood o2 and fitness recovery & VO2 estimates etc, but it loses the compass, barometer, a physical button (bizarrely imo) & a few month(s) of battery life. The OLED is certainly nicer in some situations (almost always indoors) but I very much miss the battery life. Oh, and lots of app & custom watchface support too.
Btw if you have a larger budget, Garmin is also apparently pretty good with good battery life and a very similar screen type (and much better sports tracking).