the 400% figure is extremely misleading and based on old assumptions and old battery tech.
Also it you're not keeping the phone for 20 years then it doesn't make sense to calculate "total electrons" over the absolute entirety of the battery "life".
Agreed. If you're a device maker and you haven't considered the possibility of your users plugging in their devices for long periods of time in your design, then i feel that's on you to improve your product.
I have enabled the option to limit charging to 85% on my Samsung, and last weekend I needed it to last for 2 days so I charged it to 100%. Easily made it. It's nice to know you have that 100% when you need it .