All tests seem to have failed. I'd check the system event logs on all domain controllers for clues.
Some logs I saw indicate that tombstone life has been exceeded which means that one will need to be removed from active directory and rebuilt.
Clean up Active Directory Domain Controller server metadata
Step-By-Step: Manually Removing A Domain Controller Server
Also confirm that older FRS was migrated to DFSR as this is required.
The two prerequisites to introducing the first 2019 or 2022 domain controller are that domain functional level needs to be 2008 or higher and older sysvol FRS replication needs to have been migrated to DFSR
I'd use dcdiag / repadmin tools to verify health correcting all errors found
before starting any
operations. Then stand up the new 2019, patch it fully, license it, join existing domain, add active directory domain services, promote it also making it a GC (recommended), transfer FSMO roles over (optional), transfer pdc emulator role (optional), use dcdiag / repadmin tools to again verify health, when all is good you can decommission / demote old one.
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