If you gradually put in vegetable wasts, cardboard paper, and maybe some soil, keep them airy and moist, and turn them often, in the worst case they only have a little bit unpleasant smell in the beginning. One of my compost pot is mostly indoor, it has a smell, but it’s a pleasant smell.

I live in a small flat too. Usually, I put my compost in a big plastic bucket with holes underneath, then hang it outside the window. Bring it indoor when it’s freezing outside. I also use a relatively big pot, put it beside my other plants on a window shelf. But I only put in normal garden wastes and a small amount of fresh kitchen waste, as the spaces really weren’t enough, they already take at least a year to decompose. Not sure if it’s doable for you?

Edit: They don’t smell if they decompose right.