I think you should contact redhat training and certification team " https://www.redhat.com/en/services/training-and-certification/contact-us ". They can help you better.
Speaking purely from looking things up on the internet, it seems that you should be able to do that (i.e. get RHCSA for RHEL 7, and RHCE for RHEL 8 once we have that). However, I'd definitely recommend contacting RH certification center just to make sure.
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