Much simpler way, even if not as cool: try https://apps.apple.com/app/id6444050820 that is free and great. First download a model, if you already have one you like just use the Civitai.com link, otherwise there's a selection of them and I'd try... Realistic Visions? The 8 bit one saves you a little space. Then use the photo icon in the bottom to import a photo, you want something with the face clearly visible. Use the eraser to get rid of everything other than the face. Now try prompting for an astronaut! Should work already but you can try adding Controls: Tile, Inpainting and Pose specifically.

Performance wise you can go at the bottom of the left side, click on the cpu looking icon and select (if it's not selected already) Use CoreML: Yes and for the CoreML compute units go with All.

My M2 Mini takes a dozen seconds for a normal generation like that. With the Control modules and Inpainting is going to be a little slower obviously but hey, it's a fast app.