Animation Won't Properly Convert to a Rag Doll

I’ve seen a few other topics like this, but none of the solutions seem to work for me. I’m very new to Unreal, and would greatly appreciate any advice or help on this matter!

So, I’ve been following along with Virtus Learning Hub on Unreal Engine 4 tutorials, and I am creating a zombie FPS game. Right now, I have it so that after my zombie AI’s health is less than or equal to zero, they will die. I flag them as dead and then play a death animation. After their death animation, I’m trying to make it so that they have the physics rag doll effect and the player can move their body around just by walking over them. My blueprint for the zombie AI is set up as follows:

I only included the bit where I am working with the animation; i.e. just the death routine. For the mesh and capsule, I have the physics set up as such:

I’ve spent about 3 hours playing around with these settings, and it feels like no matter what I do, I just can’t get that ragdoll effect. Worse yet, something weird is happening when I kill the zombies on a landscape. Depending on which direction the zombies are facing when I shoot them, they appear to float above the ground (on a hill), or will actually disappear through the landscape almost completely (as you can see below).

I’ve tried fixing things by changing my capsule collision to nothing and then the mesh collision to block all, but then in that case the zombie will just fall right through the ground!!! What could I be doing wrong here? I’m pretty sure this is an issue with how I have my collision set up, but I just can’t seem to find out where. Would really appreciate any assistance.