is charging with CC/CV bad?

It’s from a company that’s using a new charging algorithm meant to protect battery life.
Mostly about cellphones and such devices that are on continuously, have to raise their power to reach signal towers, and get recharged fast —- so the discussion is not specific to flashlight use

From their website there are links to a lot of review/discussion articles, e.g.

I don’t understand the collision explanation. It doesn’t sound likely that lithium ions that should have the same (positive???) polarity and thus should repel each other would collide and somehow form a deposit of lithium metal, but it has been years since I touched a chemestry book.

It sounds like the basis of their algorithm is that you can charge faster at low states of charge than at high states of charge. This is because at high states of charge Li ions are going into the carbon anode, but there are already lots of Li ions there, so Li can instead plate as a metal on the anode, which is bad.

There is nothing intrinsically harmful about CC/CV charging, but the process can be sped up by charging faster at the beginning then tapering off the charge current. New phones and electric cars already do this.