Yes a phone has a single cell and yes EV packs have many.The...

Yes a phone has a single cell and yes EV packs have many.
The rest of your statement is not correct.
https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
In summary fantastic cycle life is had at 3.92V a cell (Generalization, chemistry dependendent.)
Trade off is capacity ver cycle life.
Of course DOD, discharge rate, temperature come into play and how long are the cell or cells kept at 4.2V affects their life.
Intelligent home storage for solar (3rd gen in design) won't take a "full charge" until closer to the end of the day in an attempt at prolonging calendar and cycle life. It is all compromise with many moving variables.
Telsla cars only charged to %85 (from memory) unless you ask it for %100 due to a planned long trip.
Want your phone to last extra years, take it off the charger at %90 and don't leave it on the charger overnight.

On the subject at hand, the end game is autonomous EV and the public won't bother owning a EV. The fleets of the future will also provide grid balancing. Super fast charge just won't be as relevant and is a transitional phase as the generations/expectations change. It just won't be economic to own a car. A challenging thought to today's materialistic society no doubt.