I mean looks isn’t even really the thing, The main 2 things are default programs, and the package managers. IE arch based are good if you want the bare minimum, and for most packages to be the bleeding edge. Buntu based if you want the default packages to be more stable versions (at the drawback of not always getting the latest without setting up a repository).

Basically it’s the installers and configuration tools that are the main differences. You are right that on a practical level if you ask me to make an arch system look like a debian or ubuntu system that’s set up the way you like it, I could almost certainly make it barely distinguishable.