Can I play an animation for a Mesh without ANY anim blueprint work?

I am able to specify a Mesh, and play an animation on it using:

m_poMeshComponent->PlayAnimation(m_poCurrAnim, bLooping);

This fires off the animation without any problems. The trouble with this function is there does not appear for me to be able to fire off another animation or blend between two animations (in/out blends).

There are other functions referenced in the AnimInstance class that seem to have some of these concepts but I am unable to get them to actually animate:

m_poMeshComponent->GetAnimInstance()->PlaySlotAnimation(m_poSequenceBase, SlotNodeName, BlendInTime, BlendOutTime, InPlayRate, LoopCount);


m_poMeshComponent->GetAnimInstance()->Montage_Play(m_poMontage, InPlayRate);

Just a little back story…We have hundreds of Meshes. I do not want to force our artists to create hundreds of AnimationBlueprints. I originally was using an AnimationBlueprint to setup the animation transitions in a State machine, but then as we began to iterate, it became clearer that this was creating a bit of technical debt in that if we got dozens of blueprints online, and needed to make a simple change to one state machine, we had to duplicate that work for all of the blueprints. They are the exact same, but the State machine logic cannot be abstracted from the Mesh it seems. Due to that, I wish to just take a mesh, tell it to play an animation in code, and have it nicely blend:

Idle → Walk forward → Idle (no popping because blend in/out is working)

There are No animation blueprints being used now. Is this feasible? What is the appropriate way to handle this?