Replacing your battery every once a year seems extremely excessive. I replaced my old redmi note 7 battery only after 5 years for about $30 at a 3rd party retailer.
I think current xiaomi gives at least 3 years of OS updates on their budget redmi lineup and more on their higher priced series.
Perhaps you should consider getting a fairphone if its available in your market. Having a user replaceable battery is much better than going back to the OEM.
Maybe your battery issues is due to li-ion chemistry used in Samsung/LG instead of li-polymer more commonly found in Chinese OEM.
https://www.androidauthority.com/lithium-ion-vs-lithium-polymer-whats-the-difference-27608/