You can also bake sourdough bread - i.e. without yeast - with the appliance. Then you don't need sugar either.
However, a little experimentation and a few attempts will be necessary. There are many videos on YouTube about sourdough bread. Recently I've seen machines where the corners in the dough container are even more rounded, that's a small flaw in this machine. You always have to use a spatula because the stirrer doesn't reach the corners, depending on the type of dough.

The yeast needs the sugar, without the sugar the bread will not rise properly. I would therefore not leave out the sugar. Maybe you can experiment and reduce the sugar a little.

Yes, you can also bake cakes. But the result is not as nice as in the oven. There is a menu where you can set the baking time (menu 18, I think). Depending on the recipe, you can set the baking time here. At the edge, these cakes become relatively dark and dry. And it has already happened to me that it was not quite "done" in the middle. You probably have to try it out. I then switched to the oven for ready-baking.