Actually your fireplace looks nice. Paint the mental black first and see how it looks. If you like it, you can bring more black into your room through fabric and furniture to tie everything together.

You do not want to cover those vents up. You can re-finish the black in a heat paint in a different color. I am not sure how many colors are available but surely you can find a color to work with.

I don't think you can cover up vents. But I agree the fireplace is dated. It should be a focal point. So using stacked stone all the way to ceiling would be great, do hearth too. I would go the gray tones. Then paint all walls a dove gray. Benjamin Moore has some great colors. Paint all trim a white. For a more updated look.

By the way, the black will look fine with new stone.

If stacked stone is out of your price range, you might just replace the mantle. For some reason, that fireplace looks to me like it needs a straight slab mantle. Whatever you do, DO NOT cover the vents.

I would keep the black and also consider painting the mantle. If funds permit you can tile over the brick and give it a total new look.

You can not tile over brick without dry wall first. To the ceiling stone will change this whole room. There are faux looking stone than can work to. Check both out. Bring samples to,your home to ck color.

If you want to do very little without spending much, I would paint the mortar a traditional grey and leave the brick alone foe now. Change or paint the mantle. Yes, that black enclosure is a safety item that can't be altered.

You have a white washed fireplace posted as a favorite that I think you could copy.