Generate a base image with flux + hyper 8 step LoRA then upscale denoise and do an other 4 step sampling. Finally it does some post process with film grain to try to mimic a photo.

This workflow use the Ksampler node with negative prompt so it is not fast even if it use 8 step. It is still a bit faster than doing 20 steps with the SamplerCustom.

It use a couple of custom nodes so it might be a good idea to get ComfyUI Manager to install the missing node.
https://github.com/ltdrdata/ComfyUI-Manager

There is a bypassed second prompt and model loader. Can be enabled and connected to the second sampler to do hires step with an other model. By example it works with two step when using Flux Schnell.

There is also multiple saving node. On top right the extended node can save in webp with the workflow but it don't have meta for Civitai. Then in the bottom there is the image saver that include Civitai meta + Workflow in PNG but it can only do Civitai meta in Webp. I haven't found one that can save both Civitai Meta + Workflow intro a webp.