There were 18 running backs taken in the 2023 draft, and Kenny McIntosh was the last one. He was listed in the top 10 by many draft sites before the combine and his pro day, but fell in the rankings over time. Some people however, like Maurice Jones-Drew of the NFL Network listed McIntosh at number 7 on his list of RB prospects even a few days before the draft.
I'm not sure why he fell in the draft, although I assume it was a combination of his slow (4.62) 40 time or his lack of production. He also didn't have the gaudy stats that a lot of the drafted RBs had--he had 859 yards rushing, 505 yards receiving and 12 TDs. He didn't have over 1000 rushing yards as many of the other RBs because he shared time with Daijun Edwards, with McIntosh getting 149 carries and Edwards getting 139.
It will be interesting to see how he does in the pros. 4.62 isn't exactly slow. Emmit Smith ran a 4.7 40, but he had a pretty good career. Larry Fitzgerald and Jerry Rice, at a position where speed is more important, had successful careers with 4.7 speed. (Chris Carson, btw, ran a 4.58 40.) I'm intrigued by his skill set--especially his ability to catch the ball out of the backfield.