Hello @MEYER, JASON ,
Thank you for posting here.
As I understand, you have one-tier enterprise CA in your AD domain.
Based on the description "still have that backup from the OLD CA.", do you mean you still have the old CA backup before deleting the computer account for the CA in AD?
If so, you can try to restore the CA backup to the restored the computer, then check if it helps.
Step-By-Step: Migrating The Active Directory Certificate Service From Windows Server 2008 R2 to 2019
https://techcommunity.microsoft.com/t5/itops-talk-blog/step-by-step-migrating-the-active-directory-certificate-service/ba-p/697674
Tip: You can do similar test in your lab first, if everything is OK, you can do it in your production environment.
Should you have any question or concern, please feel free to let us know.
Best Regards,
Daisy Zhou