Rattle coming from engine bay when revving in stationary

[okowlessar]

Hi all, my 2020 RS4 has developed a rattle - sounds like metal on metal or like a stone trapped in a tin can, when gentle revving the engine. I've recorded a vid with sound, how do i upload it??

Engine Rattle (LINK)

Had the engine cover off and engine heatshield, nothing seems loose and the sound was still present even with the heatshield off. Any ideas folks?