Because you mention "bored", I suggest you see this past post:
I don't think Brussels is worth five nights, but it's very easy to get to Leuven, Mechelen, and Antwerp on cheap, unreserved trains, several times an hour. So there's an easy solution to your boredom. I'm astounded that busy, visit-rich Antwerp wasn't on your first list. Only because it sounds like your first time in Brussels, you might want to check on negative reviews of Rue de Bouchers restaurant business policies. (No current information available from me ... ) It's still worth seeing, if you can reject the touts.
I'm not that interested in breweries, but I wonder if you will miss having a car to get to smaller ones. I don't imagine that a giant brewery in Belgium is that different from a giant brewery anywhere else. You should also research tour hours in advance, so you make a good use of time and travel. This section of Belgium can have very bad business-day traffic jams.
You don't say if you like museums, but Antwerp and Brussels are full of excellent museums and interesting churches. Check on closing days. Note my remarks on a few Sunday-only excursions in the linked discussion. I don't follow Christmas Markets.