Why are my loaves gummy with anything other than AP flour?

I have a great recipe using AP flour I use almost every time I make sourdough and I’ve got it down good and it always makes a good loaf - pretty, bubbly, good spring nice crust.

Anything I make a loaf with something other than AP flour, even when I just add 10% to my current recipe, it’s gummy as hell.

I have used einkorn and rye and a fresh milled whole wheat flour (I had good results using partial this one in cinnamon raisin loaf) and it always is gummy.

What’s going on here?