instead of oat flower or in addition to, try tapioca flour. I think tapioca flower has that slippery quality that would work really well to eliminate the tackiness in your recipe. it is what boba balls are made of after all and they go down pretty smooth. its shelf stable as well.

its the best idea I’ve got. here are my other ideas anyway.

gluten free instant potato flakes

pectin

im also allergic to wheat and I like to cook and eat tasty things