Clips of Oppo Reno Ace smartphones being charged have been shared on social media platforms that might astonish those who haven't yet had the fortune to try out some form of fast-charging feature with a smartphone yet. However, there are concerns that the high charging speed will result in premature battery degradation.
https://www.notebookcheck.net/Clips-of-Oppo-Reno-Ace-being-charged-will-banish-ugly-memories-of-overnight-charging.440723.0.html
People commenting on the thread doesn't necessarily make things true.
Fast charging can reduce battery life, but batteries with lower internal resistance will be able to charge faster without much damage. There are 18650s able to fast charge at 10+ A.
So these batteries may be able to charge all that fast and keep decent cycle life.