I have tried various approaches and everything that works seems to follow the principle of laboriously spelling everything out for Flux (to prevent it from defaulting to its standard look).
define the painting approach (realism in this case)
seems to work for you. The prompt looks like a revised prompt - I just posted something done with a Lightning model where I adapted a previous revised prompt
The painting features precise detail, realism, and naturalism. Figures and objects are anatomically accurate and display a deep understanding of perspective, creating depth and dimensionality.
Lighting is soft and diffused, often from a single source, with gentle shadows enhancing forms and textures. ...