Would be nice with studies where they compare specific battery chemistries (all the different additives within the Li-ion family) vs sum charges vs charging speed vs temperature during charging vs min+max capacity range vs time.
Car batteries have a very wide range of chemistries, and they also have incredibly wide range of capacities, abuse tolerances and lifeexpectancy. There are some user generated mini/meta studies where the assumed best chemistries can tolerate wear and abuse similar to diesel engines, but they always come with the restriction of controlled temperature.
And that's why I recommend slow charging. To keep the temperature low. We all have held a hot phone.
Would be nice with phone specific studies so they can also look at the added heat from CPU+GPU, the different ways to dissipate heat, and not stop the study after 1-2 years just couse a group of users replace the phones at that point.