I highly suggest visiting the MORC website (https://www.morcmtb.org/trail/) and exploring it a bit. Within 30 minutes of Minneapolis there’s a lot of riding, but Cuyuna will put you 2 hours outside of that ring. If you’re willing to drive that far definitely consider riding in Duluth as well.
As far as good riding within that 30 minutes, Theodore Wirth Park is right in Minneapolis. Lebanon Hills is good, as well as Murphy Hanrehan and Elm Creek. Don’t be afraid to cross the river to Wisconsin and hit the White Tail Ridge system in River Falls, and a little outside your 30 minute drive is the Woolly Trails in St. Croix Falls, WI (Closer to an hour).
The trails in Red Wing, MN would be worth looking at too as you could hit it on your way home if your route allows. And if you were exploring trails on your way home you could certainly follow the Mississippi down and ride in Winona, MN and LaCrosse, WI for some excellent views of the river. Decorah, IA wouldn’t be out of the question either, but be prepared for some fun climbs, the descents are worth it.