How to properly charge iPhone?

Hey,there’s much myth going around the internet,and im wondering what is the best way to charge the phone?I heard tou need to keep it around 40%-80% and not charge it overnight so the bettery ,,will last longer,, ,but i also heard that its totaly fine to charge it whenever you want and as much as you want,so the overnight charging is fine too.Apple has recently added feature Optimised Battery Charging,so that option is supposed to save your battery lifespan when you charge it overnight.

Did someone try both options and ehat is the best way to increase battery lifespan and get the most out of it.

Hope you understand my question and have a nice day. :)