Shadow Pass in Movie Render Queue

Hey there. Has anyone figured out, how to make a shadow pass in Movie Render Queue?

I followed various tutorials today for creating shadow catchers and found some people saying “it’s not possible” while others said “should be doable”.

Has anyone by any chance managed to render out only shadows with alpha? Preferrably those created by a Niagara System?

unreal got alot to go in VFX department… so many important factors missing