Do we still need to let our electronics completely die then charge them 100% when we first get them?
no.
just plug it in and let it manage things.
It is not a bad habit, but hardly necessary.
What would be better, is if you’re going to be leaving it without using it for an extended time, is to let it discharge to around 50% so that there is an equilibrium. This is why you receive devices charged to between 40 and 60%
You can also use battery storage mode
No, this show you don’t understand a 30k foot view of what a LION battery even is, that has nearly nothing to do with it. It does help, but it doesn’t magically block off the sides of the battery from each other. I believe it more or less blocks the battery from the components on a nonphysical level.
50 percent is not equilibrium, zero percent is.