Thank you for your LORA! Pixel art is so amazing~ I repeatedly tried my favorite checkpoint to find a suitable tag, and found that Highres.fix and steps is very effective in improving the quality of the output. There are also differences in the choice of upscaler. I think the best sort is SwinIR 4x > Latent > none >r-esrgan 4x+ anime6b, but unfortunately none of them are as clear and delicate as your sample. Continue to study!