Optimized battery charging probably does things beyond what I have observed. What I observe is my phone is never charged above 80%. I don’t do videos (and other heavy power uses) and I do charge every night. So the system knows I will not run out of juice even if my battery is only 80% in the morning.
For sure filling a lithium battery to 100% or draining to some number in the 10% or lower range does degrade the total amount of power the lithium battery can hold. This is beyond the number of cycles issue.
Another thing that hurts lithium batteries of rapid charging. As a Tesla owner, I am well aware of these issues.