My oily scalp smelled awful until I stopped over washing it
I used to wash my oil scalp daily because of the oil and smell in my scalp. You can literally see the oil in my hair coming out of the scalp.
So I was washing every single day, sometimes twice if I'd been sweaty, and my scalp just stayed oily. Like, within hours of washing it would already feel greasy again. I don't know if it was the harsh shampoo stripping something, or irritation, or honestly just my baseline, probably a mix. But something wasn't working. I eventually tried spacing washes out by a day, which felt disgusting at first, and then another day after a couple weeks. It wasn't some magic fix but my scalp did seem to calm down a bit over time. Could be coincidence, I genuinely don't know.
The dry shampoo thing is worth mentioning because I was using it wrong for ages. I was basically replacing washing with it, which just meant I had oil AND product sitting on my scalp. It works way better as a bridge, like, to get through one extra day, not as a substitute for actually washing. When I started using way less of it and only at the roots, it stopped making things worse.
I also started paying more attention to what's actually in the shampoo. Nothing fancy, I just started looking for things like salicylic acid or zinc, which seem to actually do something for scalp buildup rather than just cleaning the hair shaft. Whether that made a real difference or I just felt better about it, hard to say.
Anyway this is all just what worked for me, or what I think worked, I'm not totally sure which changes actually mattered. But if you're stuck in the same daily wash loop and still smelling oily by afternoon, it might be worth messing around with the routine a bit.
Apology for the long post, just sharing what I experienced and learned for it.