This year will be time for migration from an on-premise customer environment to the Cloud which is not a very easy task with all unknown complexity compare to on-premise.
My recommendation: if you have the plan to migrate the application to Kubernetes architecture first to migrate your on-premise environment to the Cloud in order to discover all specifics, what is supported and what is not supported from infrastructure, Application, Database etc.
You can check also the following blog for WebLogic 12.2 and Database 19c support matrix - http://dirknachbar.blogspot.com/2019/06/oracle-19c-certified-for-oracle-fusion.html
Now is time to add our ssh key into the pageant, you can download from the following link
- https://www.chiark.greenend.org.uk/~sgtatham/putty/latest.html
Open pageant and load private key

This year will be time for migration from an on-premise customer environment to the Cloud which is not a very easy task with all unknown complexity compare to on-premise.
My recommendation: if you have the plan to migrate the application to Kubernetes architecture first to migrate your on-premise environment to the Cloud in order to discover all specifics, what is supported and what is not supported from infrastructure, Application, Database etc.
You can check also the following blog for WebLogic 12.2 and Database 19c support matrix - http://dirknachbar.blogspot.com/2019/06/oracle-19c-certified-for-oracle-fusion.html
Oracle Database Migration from non-cdb to pdb - components issue
We decide to create a new CDB container instance with version 12.2.0.1 in order to plug into non-cdb database which is converted to pdb.
The task is very simple, we have to create a new pluggable database with NOCOPY option due to the fact that all data files are in place and we don't need to use COPY option because all datafiles are on the correct location.