Loop 3 is NOT what I would really consider a proper MTB route. It is however a nice Gravelbike loop. Some shor sections of singletracks, with only 4 or 5 technical sections over the full distance.
I took my MTB having got the loop from a european website and chose this one for its 33km / 715m climbing (21Mi, 2350ft). It was a very dissapointing MTB loop, but wouldve been great on the gravel bike.