Realistic AI Shadows

Still waiting for something like this. I've been using Google Gemini to add realistic lighting and materials to screenshots of 3d architectural models, but the big limitation right now is the input and output image size/resolution. I tried solving this by using Photoshop, selecting the entire image and using Generative Fill but the tool apparently does not work like this. It sees the selected area as "black/empty" instead of keeping the original image context when taking into account my text prompts. I select the entire image and tell it to add realistic lighting, and it makes a totally black image with a cartoon spot light. I select the entire image and tell it to add realistic grass and sky and paving, and it makes a completely new cartoony image of 2d grass and pavement and sky...

I am hopeful that Adobe will add a full-resolution option in the Firefly web app to upload a starting image and ask Firefly to modify it.... or even better, if they add an option similar to Generative Fill in Photoshop that takes the original content into account instead of trying to entirely replace it - maybe called something like "Firefly rework". My main hope in doing this in Photoshop instead of my current workflow in Google Gemini is to maintain a high level of detail and high res image, instead of dealing with Gemini's 1024x1024 downsampling.