Textures do not affect draw calls, materials do though. If you can reduce the number of materials or objects by combining some textures together then that can help. However, if things tend to be the case that the other objects that use a material/texture are not actually on-screen together then you’d be wasting memory loading a texture where most of it isn’t being used.
It’s often a matter of balancing memory and draw calls to get the best performance.
Also, UE5 is not totally different code, it certainly reuses a bunch of stuff from before that didn’t need any changes.