I don't care how good of a season that Smith had... there are some size flags on him that may cause him to drop a bit.
I know there are a lot of folks on THIS website that really love him, but there are a bunch of 'bama fans here, and a bunch of other fans who have heard nothing but Smith, Smith, Smith... for so long, they've been talked into him.
Hell... he may end up being very good... even a star... but the size questions will follow him until he proves that he can actually be a #1 WR in the NFL. ...and doubts cause players to slide.
Now... mock drafts are just an exercise... and not even all that accurate really, but Smith's position has been tending down week by week, and his immediacy advantage from playing in 2021 slips away.
I'm sorry, but taking him at #3 as the very first non-QB, when he is undersized is a foolish move. Out of that slot, you need to be better than an okay player. Taking him at 8 or 12 makes a bit more sense, but is still a risky move. If he slides into the bottom of the first, where undersized receivers actually start coming off of the board, then ok.