Hello
Thank you for your question and reaching out. I can understand you are having issues related to SYSVOL folder not sharing.
It can be issue with network connections that blocking Traffic of AD . Disable any Antivirus program or Windows firewall you may have for temporary purpose.
Please try to force an authoritative, or non-authoritative synchronization for DFSR-replicated SYSVOL (like "D4/D2" for FRS)
https://learn.microsoft.com/en-US/troubleshoot/windows-server/group-policy/force-authoritative-non-authoritative-synchronization
Please verify on new DC ip should be of Health DC and not of your Firewall or Router ip.
https://learn.microsoft.com/en-us/troubleshoot/windows-server/networking/troubleshoot-missing-sysvol-and-netlogon-shares
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