I had the same issue, Mediterranean Olive skinned southern European here so oiliness is always a thing -- I changed my shower filter head to a soft water filter as I live in a hard water area, and this alone made an insanely huge difference. Then I got a scalp massager (silicone) which helped get the shampoo in there.
My hair texture is consistent now even after 2-3 days, which used to never be the case. Hope this helps