Personal upscaler. With the default settings, 720p images (realistic) with a good amount of detail work best. For anime and other content, lower settings may suffice. However, you are free to change the parameters.
Adjust the First Stage Denoise and Second Stage Denoise nodes to control how much the model re-imagines details. Higher values add more detail but can alter the image more. A good range is 0.4-0.7.
Used resources:
https://civitai.com/models/277058/epicrealism-xl
https://huggingface.co/xinsir/controlnet-tile-sdxl-1.0
https://huggingface.co/ByteDance/SDXL-Lightning/blob/main/sdxl_lightning_8step_lora.safetensors