I’ve Been looking into Runtime terrain deformation and Currently out of the box unreal wont do that, As far as i know.
Now i have heard somewhere on the forum (cant find the link) that editing the terrain source you’re more than able to do so. also looking into Voxcel based smooth terrain you may beable to achieve something.
But as i’am still a newbie just looking to help others I’m afraid i don’t have a diffinative answer 