Does ndsrepair -S and Reset local schema so the Job I needed?

Does ndsrepair -S and Reset local schema so the Job I needed?

No, this won't help at all.

For clarification i'll try to sum up what has happened (and it's of vital interest that you carefully comment on each and every of the following lines:
- it's a two server tree with just one partition [root]
- the upgrades (from sp1 to sp2 and the attempt with 2023) were done on the master of [root]
- after the failed attempt you deleted the NCP server object of the master of [root] from the tree
- you then reverted the master of [root] to the sp2 snapshot
- if you now run "ndsrepair -P" on the master and select "1" followed by "10" it does show you both servers
- if you do the same on the "untouched" server you see just the "untouched" box with a r/w replica, the master does NOT appear
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Do you have some sort of backup of the "untouched" server with the r/w replica from a time where the master server's NCP server object hadn't been deleted yet? It could be a dsbk-based backup, a snapshot or a snapshot-based backup, even a file based backup would help. And it doesn't have to be a recent one. If you have one: just tell us here, but DON'T bring it online under NO CIRCUMSTANCES. Just tell us that you have one and we'll guide you through the process.
If you have no backup but support, you can call them, of course, as it's not too hard to resolve the issue with dump.