Samsung is not planning any great leaps forward with the Galaxy S21 series, according to Ice Universe. Instead, Samsung's next Galaxy S smartphones will be a conservative upgrade from this year's models, with no 144 Hz displays or ultra-fast charging. 3C certification documents have seemingly confirmed a 25 W charging brick for the Galaxy S21, too.
https://www.notebookcheck.net/Leaker-dampens-expectations-for-the-Samsung-Galaxy-S21-series-as-25-W-charging-confirmed-for-entry-level-model.498261.0.html