It is possible to paint over the bricks even with the metallic paint with the right primer.

Yes! Make sure you get the correct materials. Dytecture is correct. Don't skimp or try to go the less expensive way, you'll be sorry.

Once the primer is done, what should I do, repaint? I want to update this room, right now the fireplace is a brown blob

It has always bothered my sole to paint brick, but brick can be painted, and it works well. Houses are a blend of colors and textures, solids and voids. Painted brick can add a lot to a room as far as color and immensely as far as texture. Painting anything well is about proper prep, type of product, quality of product and application. If you don't prep it right with the right product, and if it fails, it will be an immense mess, and costly, to try and fix it. A real paint store can lead you to the proper process and product. It will look good painted. The downside is that you cannot really go back to the original brick, the paint will chip on the hearth and you will have to touch it up once in a while, if you use it or run a vacuum into it. You might want to address how the crown molding goes around the brick, probably paint it also, at least around the fireplace.

If it was in the budget I would cover it with tile or stone like this
But, since that is not always in the budget I found this article on painting brick
https://www.houzz.com/magazine/what-you-need-to-know-before-painting-brick-stsetivw-vs~4040365