Server: SSL Certificate, 2048-bit RSA Public Key, Signature Algorithm is sha256RSA

What am I missing here? !

* I've scoured the RFC's, and I have yet to find anything on how to determine the ECDHE key size (or any key exchange algorithm key size) in a TLS cipher suite. I need to confirm that ECDHE is at least 256 bits for compliance reasons.
* In both RFC8422 and RFC4492 it's emphasized that for ECDHE\_RSA, the Certificate MUST contain an RSA public key... boom got it, now how do I determine the curve's key length?

I don't understand why in SSH, a key exchange algorithm like "ecdh-sha2-nistp384" has the curve size in it (which also determines the hash size), bit in a TLS cipher suite this is not the case. 

* The same thing goes for DHE\_RSA\_WITH\_AES\_128\_GCM\_SHA256 - How can I confirm that Diffie Hellman Ephermal is 2048 bits?

Is there other information I need to be looking at besides the Cert and the Cipher Suite? Do I need to dig into the code? Thanks in advance for any assistance with this!