I would honestly love for phone manufacturers to outright build in some software to build in best practices if they actually exist. Don't let me charge to 100% at first or something!
In the most recent iOS versions, if it can determine when "clean energy" is available near your location, it will also try to charge only during those time periods. I don't think any 3rd party has determined if it is effective.
Just gimme a slider that lets me tell it to only charge to 80% and be done with it.
Their help portal has a research summary explaining their sources (the most recent of which is from 2010, so battery tech has likely improved in some respects but it's still a useful reference point): https://accubattery.zendesk.com/hc/en-us/articles/210224725-...
Phones typically are geared to use the full capacity of the battery.
The demand towards the thinnest phones possible leaves smaller tolerances towards cramming in the biggest battery possible.
I think the galaxy note 4 was the last one with a removable battery therefore something that could run a long time.
An external battery case depending on how you use it can extend the lifespan of an internal battery too.
My electric car by default only charges to 80% unless you tell it you're planning a long drive in order to conserve battery life.