What brush set should i buy?

I’ve been painting miniatures for a year and a half, but i only used two citadel brushes until now, and now these brushes are really worn out. I wanted to buy a brush set that could last me long, but i can’t quite decide what to buy. I’d like to have good quality brushes, but i don’t know the differences between brands and don’t really know well which brush sizes are a must have and which are not. I did some researches and i feel like i should buy natural sable ones, or at least buy a set with both the natural and synthetic brushes. In that case i’d also buy some brush soap to take care of them. I was thinking about buying the rosemary&co “miniature brush set”, but i wasn’t fully sure.
My budget is around 40€, i’d appreciate a lot some advice.