Batteries are nonlinear chemical cells that age from temperature rise, excess voltage and insufficient voltage. LiIon are fairly linear on the VI curve from 3.8 to 3.4V but also have a secondary large capacitance with a higher ESR that requires "soak" time this is done during CV as the current declines and cutoff is usually defined at 10% CC rate.
Studies ( research Battery University) have shown that the total lifetime Ah capacity can be doubled by reducing the capacity 10 to 20% by reducing the CV terminal voltage down to 4.0V The ageing is somewhat exponential above this and starts by increasing self-leakage then ends up as self-heating with more voltage going from 4.1 to 4.3, so most chargers use 4.20+/- x0 mV. but reducing CV to 4.0V will multiply your lifespan in terms of cycles before capacity drops 50%. Even raising the threshold for Depth of Discharge to 50% can increase lifespan. It just means shorter use time and more batteries needed but ends up extending the charge cycles more than 4x.
I don't have the charts I computed at one time and I am just doing this from memory.
YOur mileage may vary with battery chemistry, and degree (<< 1%) of mismatch in series connected cell capacity as the weakest cell ages the fastest and becomes 1st to drop below 3V accelerating Dendrite growth which can short the cells internally.