We’ve found store bought oat flour to be different than homemade. We prefer the texture to store bought and suggest that is what you use.
If you have an electronic scale at home please use it to measure the flour, as these flours are notorious for being difficult to measure with cup measurements.
If you oat flour or coconut flour is very clumpy sift them after measuring.
Find it online: https://lexiscleankitchen.com/healthy-carrot-muffins/