Use Microsoft Store app to fix Forza Horizon 5 'Your game needs an update: Error' through launcher

If, when launching Forza Horizon 5 on Windows PC, your game informs you that 'Your game needs an update' but the update progress meter bar simply reads Error (whether this be through the Forza Horizon 5 game launcher or through the Xbox App) then simply try to update the game through the Microsoft Store app. This worked for me and my game updated and booted as intended following the update.