Can I place my Sonos beam 2 against the wall? Does it pair well and sound better than the lg c5?

I’ve just purchased a new lg c5 and would like to know if I can pair beam easily with the tv. Is it a substantial improvement over the tv sound set up? And can the beam be placed right against the wall without any space behind it? Would this affect the performance of the soundbar? I’ll be wall mounting the tv above a fireplace and there’s this ledge above the fireplace that is the perfect size for a soundbar but there’s only enough space for the soundbar, no space behind.

Also, would a refurbished one be as good?