A simple workflow for upscale fast and keep detail on cartoon- anime image.
You need the ltx vae: https://huggingface.co/calcuis/ltxv-gguf/blob/main/ltxv-0.9.1-vae.safetensors
And custom node (thank's to midnight1111 for link): https://github.com/Lightricks/ComfyUI-LTXVideo
In the zip file you found full image upscaled with this method.
Original image size: 1376x1704
Upscale 2.5x
Result size 3424x4224
This work great with flat image, for realistic you get cartoonized style result.