Hi there,

You may try to mute them with your thumb, but I think the best way to do it, is to simply ignore those two muted strings and not strum them at all. That way you won't have move your thumb around. Check out these diagrams on the D minor chord: https://www.guitartricks.com/chords/D-chord/min

For the strings with an "x" on them, try your best to ignore them, or mute them with your strumming hand instead of your fretting hand.