This article says that for those that typically only use 10% of their battery capacity on normal driving days, setting the charge limit at 75% and plugging in at 65% yields the best battery life. (Nissan Leaf example)
I wonder if that “sweet spot” range changes from brand to brand?
It almost surely does vary from brand to brand, and from battery type to battery type (NMC, LFP, etc), and based on how the vehicle is used. Some brands have minimal battery management systems (Nissan, etc), and some brands have very sophisticated battery management systems (Tesla, etc).