i had the same issue earlier, when having redownloaded 100% of the game it gave this error being 0x80073d05 when i clicked details about the error. If you are also getting this EXACT SAME error reboot your pc and then goto %localappdata%\packages
(type it in explorer.exe address bar and press enter) and erase the Microsoft.ForzaMotorsport_8wekyb3d8bbwe
folder then goto xbox app again and press download again it then completed the download successfully
this 0x80073d05 error basically means the xbox app failed erasing that folder from a previous install, because a file or folder inside that directory was in use, rebooting your pc should unlock it and then you can erase it yourself manually and let the xbox app complete the download.