Samsung has both a Galaxy S21 5G with S Pen and a Galaxy Note 21 in the works
The S Pen-supporting Galaxy S21 5G series might be the first step towards the demise of the Note family, but Samsung is still planning to release a Galaxy Note 21 in 2021.
So whats the difference
The S Pen is a Note-specific feature. Nobody with an S series phone wants or needs an S Pen