It’s true that every battery has a charge rate curve with temperature. If you go above it dendrites and other chemical junk starts to occur and you lose capacit

It’s true that every battery has a charge rate curve with temperature. If you go above it dendrites and other chemical junk starts to occur and you lose capacity. But your phone is designed to keep track of this. Fast charging is really about getting as close to that curve as possible. Glass anodes that I mentioned above basically make the chemical damage much less possible/likely. So you could safely charge at 10x current speeds.