Second photo. There are three skylights.

It's pretty wood but if it's too much for you, you're pretty limited to painting it, which would look great, too. You could paint the walls and leave the ceiling wood, or paint the walls and ceiling, leaving the beams wood. Or paint the whole ceiling and leave the walls wood.

A much bigger job would be to strip it all and stain it a lighter/different color, if you want to keep the wood showing. It would still be a LOT of wood.

That would be a lot to paint, but would look fab in a dark, moody shade. You could also just add a large area rug to offset the lightness of the floor and live with the wood walls and ceiling for awhile. It does appear to be very pretty wood, albeit not a good match to the floor.

I was thinking of painting the ceiling cross beams white and the inside panels a different colour. I wouldn't mind ripping off all the rest of it. I am claustrophobic so this room is not a room I would want to spend time in, as it is now.

I wouldn’t rip any of it out. Paint would completely transform it, leaving beautiful character.

Paint!

Or this

Paint the walls the same as the inside of coffer

Paint it.

I would definitely love to see it lightened up!