Have you tried soba noodles? The putty color is fine in a stirfry that has colorful ingredients, but rather offputting in tomato sauce dishes. Nonetheless, I like the flavor. It is my understanding that only very expensive soba noodles are all buckwheat. If memory serves, most also contain wheat. But as the packages I see bear little or no info in English, I can’t say what the percentages are.
Whenever spaghetti squash is on sale, or included in my Misfits Market boxes, I steam or roast them whole, and eviscerate them after they cool. I AM happy with this as a spaghetti substitute.