As far as I’m aware, Unreal Engine does not support landscape modifiers (if by landscape we refer to an actual landscape asset).
There’s an old thread about this (apparently, the feature still doesn’t exist):
https://forums.unrealengine.com/unreal-engine/feedback-for-epic/26495-terrain-editing-in-runtime
If however, you find anything, pls let me know too.
glhf!