Here's the best hint you can have about how to make potatoes that are crunchier.
First, use frying potatoes, like Russet.
Grate them. If you are keeping them overnight, don't drain them, add some lemon juice and coat them.
Drain the "water" into a cup. Put the potatoes in a tea towel and squeeze out all the "water" as well. Don't discard the water.
Put the potatoes into a large bowl and microwave them, about 2 to 3 minutes until rather warm. You can mix in between and put them back until they are hot enough that it's hard to hold them.
The "water" will separate into a watery liquid and a white liquid. You can poor off the watery liquid. Put the white liquid back into the potatoes. This is actually the potato starch, which is what makes them crispy.
If you want to skip all the work, squeeze the potatoes dry, add powdered potato starch instead of the natural potato starch. Fry
I use the frozen only to make GF pie crust. The real stuff is used to make potato pancakes. Though, this is one of the few places where I will tell you that the freeze dried actually works well, too. But everything but a big bag of potatoes is a lot more expensive. I can buy 10 lbs for $2 sometimes.