devtrackers.gg
I was looking a very long time for background/wallpaper on pc but then i saw this amazing painted tachanka background and then i wondered: how can i get it ?
I don't know for sure whether that wallpaper is publicly available, however I can offer some help!
Here you go: https://www.reddit.com/r/Rainbow6/wiki/assets
We regularly update our public assets list for players to download. If the wallpaper is not included yet, perhaps it will be later
Enjoy your day!