Is your water hard or soft?
I have soft water and once I sold the hemp I just don't have stink anymore.
Sometimes I remember to add some baking soda, I often add vinegar (via the Downy ball) to the middle wash. I use any detergent. Once in a while I remember to put some TTO in the water before the first wash...
I do a short cold wash, followed by a long hot wash, followed by a short hot wash. The detergent, TTO and/or baking soda go in the first cold wash, the vinegar in the 1st hot wash, the last is additive free. I do have plenty of fleece; lots of PUL pockets and even a couple of my cotton pockets are fleece inners. I also use micro inserts.
No stink, no stain... I know you can find the right combo for you. Even my DD's inserts come very clean. (5 yr old overnight pee