Part of the problem is the cool gray paint is fighting with the warm wood floor and bricks. I’d start by changing the paint. Then hang some artwork, put a tall plant in the corner (idk if you want plants on both sides, tho).
What does the rest of the room look like?

I would need to see the rest of the house since in my head Boho and Scandinavian are polar opposites in style. What is this space ? I have to say I do not like the stone with the floor at all. I have to say I love MCM and I have a huge fireplace in my MCM ranch which is one of the features I love. It is much more in your face than that one but we actually did flooring to work with the stone.I think painting might be the answer here unfortunately unless redoing the floors is in your future . I do not think this stone was ever meant to have darker grout.That fireplace is such an integral part of the house I really think I would redo the floors before touching that FP. As for decor for it keep it simple a nice large piece of art and a real plant . I do agree that wall color does not work with either the floor or the FP so at least look to changing that.

New wall paint is the easiest fix but I also see the floor and the fireplace fighting as well.

This may be a monitor calibration issue but I see a pink undertone in the fireplace and orangey-yellow in the floor. Perhaps a lighting change would tone down the undertone differences. Or you can add an area rug with both colors to help the eye tie the two undertone colors together. Perhaps a sisal or chenille look with a little color variation.

Don't paint the fireplace, work with it. Painted stone and brick fireplaces often end up looking like plastic.

I agree with painting the walls and looking for a rug that brings together the tones of the fireplace and the floor. Once you have your furniture in the place you can decide if more needs to be done. If it were my house I would consider placing a dark brown (could also be black) chair to the left of the fireplace and a dark brown cushion on the ledge underneath the triangular wall. This would cozy up the corner.

Stain the stone almost black to create some drama in the space. Those walls are the wrong color gray. Way too blue.

OK,

I think the hearth needs separation from the floor with some contrast and the fireplace needs a door. So, have a custom made fireplace door in a bronze or iron finish and then have some metal panels made that match the door. Add a rustic mantel and a large plant on the left in a pot with some color that ties in with other pieces of decor in the room.

Add some interesting things on top of the mantel to bring in a little more color...and here's what you have:

Featured Fireplace Door: Craftsman with Fixed End Panels in Forged Iron

Mockup Provided by: The Fireplace Door Design Service at Hansen Wholesale. We supply the doors, the metal panels and the items you see on top of the mantel.

Do you want to keep the midcentury vibe or downplay it? Because I would hang something very funky and cool there. Check Etsy for real vintage wall art, or Crate and Barrel, CB2, West Elm, etc for something more contemporary. I also like that fiddleleaf fig that Hansen posted above.

Really beautiful.

Log burning? Other? Will you actually be using the fireplace?

Painted or stained dark, it would be dreary and foreboding.

Painted or stained white, it would be nothing short of cringe-worthy.

Not sure you have the natural sun light at that end of the room for plants.

Someone wanted to enable their pets and/or themselves to set atop that hearth to warm. If you don't want to do that, you might consider altering the hearth -- removing it and recreating it so the top of the hearth is floor level.

If you leave the hearth as is, then you could panel that short wall left of the fireplace and build in interior lit cabinets with solid doors below the top of the firebox but glass shelving and doors above that to the ceiling, leaving the paneling and stone visible through the cabinet. Remember to have an electrical outlet in the corner vertical between the lower solid cabinet doors. Then set a comfortable chair and sturdy floor lamp/table combo in the corner in front of that.

Either way, would not add a mantel to add clutter the top with items above it. If you do add a mantel or shelving, consider putting the full width of the fireplace wall.

You could add art to the fireplace but instead of a framed picture or poster or print of painting, consider something else -- perhaps something that reflects your interests and hobbies made from pressed metal.

Hansen Wholesale has the perfect solution! Also, please get rid of the gray walls. Gray does not work in that space!

1. Paint the walls off white. 2) Add some contrast tile or metal to the front of the hearth (black or dark charcoal). 3) Bring in a very large textural boho style area rug in cream and black. 4) Hang something sculptural (perhaps with black and some brass) over the fireplace.

I have no advice to offer except, dear God, do not touch that fireplace. To my mind it is a perfect MCM artifact.

I forgot to address the corner… a bar cart might work well there.

This thread is a year old. Not sure why it got bumped, but I'm pretty sure the new advice will not be timely for the OP.

Actually, I opened it hoping the OP had bumped it with an update. Sigh.

I am beginning major reno on a mcm home with a very similar issue (orange-y) floor beneath the carpet). What did you decide? Any updates?