Coming from Germany, I don’t know if the traditional way to eat muesli is just adding yoghurt. Most people I know normally add fresh milk to it.
Personally, I enjoy my daily Müsli with vanilla soy milk (but I tend to be the only one liking that), fruit skyr (or yogurt), some oatmeal and/or crunchy granola, and most importantly, at least two kinds of fresh fruit, like bananas, peaches, apples, pears, or grapes. Without fruit, it just tastes bland.
Still works for me without any issues