From what I found (Colmi P8) judging by display these will last just few days at best unlike Amazfit Bip which can easily last one month with always on display perfectly readable in daylight without any backlight plus allowing custom firmware. The issue with original Bip/Bip S is they don't produce them anymore, so you have to buy used (as I did after first fell apart) for like 20USD or buy some clone (also not that easy to find).
Only original Bip and then successor Bip S have battery life measured in weeks, the new versions with fancy displays have already crap battery life. In my country none of the old two is sold anymore. I don't really care for health monitoring (i need smart watch only to get and read notifications), it measures heart rate, sleep, steps, sleep is quite accurate, the others can't say.
I remember there is now basically rebranded Bip with different firmware sold under different name (Bangle.js 2 or some other unknown chinese models), but nothing improved in last few years for low price in compact body. Everything else like those Casio or Garmin watch with good displays and battery life or LILYGO TTGO T-Watch-2020 are like 15mm, more than 50% ticker than original Bip.
In addition to what Markoff said, I recommend sticking with the original Bip or Bip Lite; nothing else, including other Bip models. Only those two give you access to [the world's largest library of watch faces](https://amazfitwatchfaces.com/bip/fresh).
I like Bip so much that when it failed (because of a design flaw fixed in Lite and later Bip models), I bought Bip Lite (since I never used Bip's GPS, always using the phone's instead).
I just found Garmin Approach S20, they seem relatively thin, use MIP display and should have also battery life in weeks used as smartwatch without GPS.
Dunno what's their website, it is not sold in any online shop in my country, only power hungry successors are sold. Care to link site where they are still selling new Amazfit Bip or Amazfit Bip S?
The firmware can be replaced with your own.
The battery won't last a year though.