Hi,
As Andre correctly pointed there is not way way for consolidation.
You need to decide on few things before you can fix this
Before jumping into cleanup, recommend establishing a cross-functional item governance team
1 - New item which will replace existing items. Define naming conventions, unit standards, and approval workflows.(This ensures future consistency and avoids repeating the problem)
2 - Units to be used for the new item as existing duplicate items have different units
3 - Close all items open transactions as they cannot be moved to the new item
4 - For future demand start using the new item master created
5- Gradually all old duplicate item's open transactions will be closed.
6 - Put all old items on hold and block them for future use
7 - Move all the stock for all duplicate items to the new items once all open transactions are closed for duplicate items. Set old items to “Discontinued” or “Obsolete” by using product lifecycle state.
Once all above is done you are good for a clean future but note that all historical transactions will remain linked to the original items for audit and traceability. The new item will be used only for future operations.
There is no easy way to fix this and will require very careful approach to move from many duplicates to one new item
