Input your desired output final resolution, it will automaticaly set the initial recommended SDXL ratio/size and its Upscale Factor to reach that output final resolution, also there's an option for 2x/4x reverse Upscale Factor. These all to avoid using bad/arbitary initial ratio/resolution.
https://github.com/marhensa/sdxl-recommended-res-calc
git clone https://github.com/marhensa/sdxl-recommended-res-calc
comfy node install sdxl-recommended-res-calc