Image generation models running locally on limited resources [P]

I have a project consisting of generating high quality covers out of its content. On my 16GB of ram machine with no gpu, i have tested the opensourced stable diffusion models without any success. All return bad quality covers with blurred faces and scenes that do not match the prompt whatsoever. So, i have switched to generating the images with google imagen models which gave me outstanding results but for a short period of time since i cannot afford hundreds of generations due to my limited financial resources.