Your images look plastic because you keep adding polish instead of taking it away. Here are the five 35mm texture plates I overlay, and the exact settings that stop AI looking like AI.
advert of [your subject], 35mm grain, halation, ARRI Alexa
chaos 10 ar 4:3 style raw 80mm lens at f/5.6 atmospheric haze diffused softbox
Magnific → Magic spell → Skin Enhancer Optimized for: Enhance everything Sharpen 28% Smart grain 17% Version v1 (flexible)
A generative upscaler rebuilds real detail. Post-added noise just sits on top of a plastic image.
Drop a dust mask over your image Blend mode: Screen Opacity: 100% (dial back to taste)
Five plates, 2160x3840. The four black-background ones go on Screen (black drops out, texture stays). The grain plate is mid-grey, so put that one on Overlay or Soft Light.
01_dust-and-hairs scanned negative dust + hairs Screen 02_scratches tramlines, cinch marks Screen 03_lens-dust backlit dust motes, bokeh Screen 04_light-leak warm halation bleed Screen 05_film-grain real silver-halide grain Overlay / Soft Light
Imperfection is the new luxury. You're not prompting anymore, you're art directing. The taste is the moat.