The state legislature has been competitive, but the Senate seats have gone pretty reliably for DFLers in the 21st century; the two exceptions were when the incumbent died in a plane crash a week before the election, and when they (barely) kicked out in 2008 the Republican who had (narrowly) won in 2002.
(Gubernatorially, Republicans won the first two elections of the century but DFLers have been in office since 2010, which was notably a red wave election both nationally and in non-statewide races. On that topic...)
Even if Klobuchar retires (and I doubt she will, since she's not that old), is Flanagan really a shoo-in for the DFL nomination?
I have no idea about Walz. I know some people who are sore about stuff he did during the pandemic, but I think by 2026 that'll be old news. However, it's worth noting that although there are no term limits it
does not appear that any Minnesota governor has in fact won a third term.
edit: I stand corrected. Rudy Perpich inherited the second half of a governorship, was defeated for reelection, then was elected and reelected, and then was defeated going for his fourth, not third, term.