Image generation models running locally on limited resources [P]

I have a project consisting of generating high quality free ebook 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. So, having said that, is there a model that comes close to what google models provide, that runs locally on my 16GB no-gpu machine (even if it takes 1 hour to generate a single cover) ?