From “Engineering Explained.” He says that as you charge/discharge, the random orientation of microcrystalline structure in the battery combined with expansion/contraction due to Lithium migration results in forming cracks in the particles, which then results in reduced battery capacity. I’ve been letting my battery get down to 50% or so before bothering to charge back up to 80%, I may default to 70% and charge after every trip instead. (For a Volvo with NMC chemistry I’m not sure if I have “high nickel content” and would benefit form staying below 75% or not.)
Plug life advocates the 80-20 scheme, but also batteries that are thermally managed don’t need too much babysitting. Also charging over 60% is where battery damage tends to happen.