DB migration Oracle Oracle DB 12c R2 -> Oracle DB 19c ->MS SQL 2017

Hello,
we are currently using Windchill RV&S Server 12.3.0.2 Build 1 API 4.16.1 connected to Oracle DB 12c R2.

We would like to switch to Windchill RV&S Server 12.3.1.0 Build 4583 API 4.16.4583 connected to Oracle DB 19c.

And later on switch from Windchill RV&S Server 12.3.1.0 Build 4583 API 4.16.4583 connected to Oracle DB 19c to Windchill RV&S Server 12.3.1.0 Build 4583 API 4.16.4583 connected to MS SQL 2017.

Is there anyone with experience linked to this topics?
What is your recommendation to proceed.