Custom Content is not going to help the underlying cause when you create your Sims to still look similar. As others have already pointed out, the tools are there in CAS but you can't be afraid to experiment because you may have in your mind that all Sims must look like this or that.
Perhaps try this. I edited these role Sims by using the presets available and then making minor adjustments with the sliders, if at all, for some features. Hair color, skin tone, eye color and weight I kept the same but it doesn't matter if you do or not. Just have fun.
https://i.postimg.cc/bvqNMh6c/Screenshot-2658.jpg
https://i.postimg.cc/j55qxh0M/Screenshot-2660.jpg
https://i.postimg.cc/QNv7zF12/Screenshot-2664.jpg
Don't forget to save your Sims so that you can use them again, etc for future use.