Please take into account that both the old and new endpoints return the certificate of the CA that was created when the RHV/oVirt engine was installed. But the RHV/oVirt administrator may later replace the certificates, specially the web server certificate, see [1]. If that happens the CA certificate obtained from those endpoints won't work to connect to the engine. I'd suggest that you take the certificate directly from the SSL handshake, that will always work.

[1] https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Virtualization/3.6/html/Administration_Guide/appe-Red_Hat_Enterprise_Virtualization_and_SSL.html)