ArcSDE User-Schema Geodatabases in Oracle are deprecated
!!! IMPORTANT !!!
Do you have customers on Oracle 12c – 12.2.x or 12.1.x ???
If you do, then inform your customer that Oracle 12c 12.2/12.1 have reached End of Life and Oracle strongly recommends upgrading to 19c.
Oracle Enterprise Geodatabase SDE Repository Upgrade using an Oracle Restore Point to Rollback the changes in case of problems.
Pro Branch Version & Oracle Table Compression
How to Load a Large Featureclass in an Oracle Geodatabase.