Merging materials and reducing draw calls

Saw this older thread which talks about Texture Samplers and Texture arrays.

Merging materials inside Unreal to reduce draw calls. Can someone share their workflow for doing this? Is a 3rd party plugin like MeshBaker required?
I’m familiar with the process inside Unity but very much a novice in optimizing graphics in UE.

Unreal have some similar to MeshBaker outofthebox