The game completely crashes when I add the fireplace and the wallpaper brings up the 'Can't Apply Here' bubble. I was so excited too 
#Can't add grotto fireplace or deep sea wallpaper to my underwater home
lime dome
plush karma
Report single player crashes here #1105385747290280036 following the template in pinned post
rancid carbon
Hello @lime dome Thanks so much for your report. We’re aware that this issue is still happening, and we’re really sorry for the inconvenience it’s causing. 🙏
The team already has a fix prepared, and it’s currently going through QA testing to make sure everything works as expected before we release it.
For future crash reports related to single-player, we also have a dedicated channel you can use here https://discord.com/channels/623097219628662784/1105385747290280036.
Thank you again for your patience and for sticking with us — we’ll let you know as soon as the fix is live!