As Windows Latest observes, this is actually a traditional ‘bloom’ wallpaper, except Microsoft has redone the image in the Copilot colors (mirroring the Copilot button in the taskbar).

Windows wallpapers are seen ... as a candidate for the new Windows wallpaper. Microsoft's aim appears to have been to promote the use of its AI, Co-Pilot, which some of the photographers say ...

The latter is equipped with a new version of the standard Windows 11 Bloom wallpaper. There is also a dark variant, which is not included with the Windows 365 Link. Here they are in high resolution.