Some brands seem to make it crunchy. I just eat that like cereal with soy milk or yogurt. I made the mistake of buying cheap muesly from the local convenience store and it was exactly how you described it. It was the "let sit overnight" type. Except it had cornflakes in it that would get soggy and fall apart.
I forced myself to eat most of it, the rest went to my local murder of crows who picked at the dried fruit and cornflakes and left the oats to the pigeons to deal with. I guess I wasn't the only one who didn't like them.
As for the crunchiness, maybe try making it into granola in the oven? Not sure if that would work but it's worth a shot.
Why do I hear castlevania music in the background?