Safe in terms of winning chance, Likely D with the margin. But for some reason Smith isn't as well liked as Klobuchar.
No other Democrat in Minnesota seems to be as well liked as Klobuchar. Tim Walz won by roughly the same margin as Smith in 2018, and Keith Ellison of course ran behind them. Klobuchar seems to be the only Democrat in recent years who has run substantially ahead of the state's partisan baseline.
At any rate, this race is Likely D, closer to Safe than Lean. I agree that Smith would be in jeopardy if this were a Biden midterm.
I'm not so sure a Biden midterm will be like 2010 or 2014. Could very well be closer to 1998. But in this case, it would come down to the GOP challenger. We will see in 2026 in case of a Dem prez, say Biden is reelected or Kamala Harris takes over after the 2024 election. If current demographic trends continue, this will be a tight race that may very well go in the GOP's direction.