I agree with @Judy G Designs. The white walls that you have now would work with Scandinavian styling or with any number of styles. And white for paint is much more up to date than grey, overall. The grey fad is over. And the wall that you have that looks like a gold colored wall with the adjacent wall art with red - that is absolutely fabulous. You could definitely do something with that existing space if you wanted to. But white would be good and especially with your flloor which looks like it may have a grey cast; you can use floor color for upholstery if you‘d like, as Judy G suggested. But grey walls and grey floors at this point would give you not only a sort of depressing look but a dated look, as well. If you wanted a bit warmer white, Benjamin Moore’s Ballet White is a nice, versatile color. You could try a sample. I like BM’s Natura line.

I’d first rethink the brick wall; it could be left bare or tie it in with what you add on wall. Suggest incorporating green to compliment granite and wall color https://thecanvasmuseum.com/shop/the-spice-of-life/?utm_source=pinterest

Boho 3d morning inspiration. I was able to throw this together before looking around at my other client's projects. Thank you! A white brick wallpaper would look chic in this room! you could also post on a different site for style photoshoots. photographers would love a space like that on the off-seasons

So my understanding of a grooms room is a temporary space for the groom and his men to relax and get ready for the wedding so is this a temporary space or what ? IMO a room with no windows will feel like a box and when you add in dark walls and ceiling not an ideal place to get dressed for a wedding. You better really good LED 4000K lighting in this space for sure .I need more info .You need to post a to scale floor plan here in a comment and also all items relating to this are dealt with in comments here DO NOT start another post.