>>49790930
This is what ADetailer/inpainting is for anon.
It's not that it doesn't know how to draw nails, it's that latent space is 64x smaller than actual images, and the VAE which upscales latent space to actual outputs only has 4 channels, limiting small detail fidelity. That's why you have to re-sample small areas on an upscaled canvars, which is what ADetailer or high resolution inpainting does.