The CA is still tied to that individual node. The idea of having it is that it would give you some recourse if your identity key somehow leaked. You could use the CA to revoke the old identity and create a new one with the same CA. I believe this is in theory possible, but I’ve never actually heard of anyone doing it to recover their node.
Generally people just put all 6 files in the same folder and be done with it. Technically you could only put the signed versions of the 2 certs there + the identity key. And store the CA key in cold storage somewhere, so it can never leak.