Hello @drkr0ot777 ,
Thank you for posting here.
Before troubleshooting the issue, kindly remind that since private information and security information may be involved, the forum does not analyze logs. Please delete or remove any private information and security information in the logs and cover or blur any information you provided in the post.
Based on the description, you have added a 2019 DC in your domain.
The minimum requirement to add a Windows Server 2019 Domain Controller is a Windows Server 2008 functional level. The domain also has to use DFS-R as the engine to replicate SYSVOL.
Forest and Domain Functional Levels
Here are some suggest for your issue:
1.Please check the forest/domain functional level of your domain.
2.Please check the SYSVOL replication type (FRS or DFSR).
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\DFSR\Parameters\SysVols\Migrating Sysvols\LocalState registry subkey. If this registry subkey exists and its value is set to 3 (ELIMINATED), DFSR is being used. If the subkey does not exist, or if it has a different value, FRS is being used.
3.From dcdiag result of dc1, it seems DC1 has issue.
Before you add 2019 DC, did you check the health of DC1 and DC2?
Before you add 2019 DC, did you check the AD replication of DC1 and DC2?
4.If you can check the AD replication now by running commands below on PDC.
repadmin /showrepl >c:\repsum1.txt
repadmin /replsum >c:\repsum2.txt
repadmin /showrepl * /csv >c:\repsum.csv
If there is no any error message in the result, it means AD replication works fine.
5.Meanwhile, please try to check the issue "The RPC server is unavailable" based on the links below.
Windows Server Troubleshooting: "The RPC server is unavailable"
Active Directory Replication Error 1722: The RPC server is unavailable
Hope the information above is helpful.
Should you have any question or concern, please feel free to let us know.