Blending Between BlendSpaces, SingleAnimations, etc.

How do we go about blending between separate blendspaces and animations?

I want to achieve this purely in C++, I do not want to use any blueprints to achieve this.
The documentation seems sparse and unhelpful for the most part.

I have managed to play a blendspace by setting the animation in SingleAnimationInstance, but when it came to blending between blendspaces I had no luck finding any resources.

I tried to cast UBlendSpace into a UAnimSequence and pass that into a PlaySlotAnimationAsDynamicMontage, it didn’t crash but it didnt work either.

Can anyone point me in the right direction for handling animations in C++?