Author: @seven947
Workflow source: https://openart.ai/workflows/seven947/1minute-8k-upscale/1IPTks1gL7v0EPmvsMcx

This is a workflow to quickly upscale an image to 8K resolution; just drag and drop the image and click to run. The red section contains parameters that can be adjusted to your needs.
Thanks to ControlAltAI on youtube and Kijai on github. This workflow is built on top of them and I learned a lot from their work.