As far as we know the Samsung Galaxy S21 range will only support 25W fast charging, a break from the S20 Ultra, which supported as much as 45W fast charging.
The S21 range will, however, ship without charging bricks, and pictures of a much more powerful 65W fast charger have just popped up which suggests greater capabilities.
This charger has previously been certified by Korea’s certification authority, but it is unclear if the current Samsung Galaxy S21 range will support it.
One leaker suggests support was being considered, but that ultimately plans changed.
— Snapdrachun 888 5G (@chunvn8888) January 10, 2021
This may mean we may have to wait till the Samsung Galaxy Note 21 launches before we see a smartphone which supports this rapid charger, which should, in theory, allow a smartphone to charge to full in only 30 minutes.