I'll just lay awake, bathed in cold sweat, for another night.
Ah. Ye old "save the nice one for best" philosophy.
I was taught this, also.
Unfortunately, "for best" happens about 8 times in life.
Which caused me to rethink strategy.
And buy lots of waterproofing spray for nice things instead.
That's foam board? Thought it was pink light glow--actually like the effect a lot! Softly warming.
Hmm. You get bonus points for prompt decorating.

And for not setting anything on fire with candles.

And for how "cosy woodland" is this great look.

And for NOT adding a scary horse.
I think piney garland could be good.
Something to break straight line of mantel, add puffy softness.
Or white poly-fill stuffing, with white lights underneath? To resemble snow & reflect up into mirror.
Just a touch of zing--because looks good already, honestly.