Test server configuration - certificate setup

I currently have one server in production with LiteSpeed and would like to setup a test server with the a newer version of LiteSpeed, OS and changes in the website as well.
For a testing period I would like to have 2 different (AWS) servers for a single domain (mydomain.com), and once it is validate by the user, the test server will became the production server.
In cloudfare I have an A record for all the request from mydomain.com to go to server1 (production) together with a WWW record.
I am now configuring a new A record to serve test.mydomain.com from server2.

How should I configure my domain and certificate?

I believe I would need to temporary point production DNS to test server in cloudfare in order to register mydomain.com (without test prefix) as the domain in the test server and have the certificate correctly installed. My main concern is if this procedure will affect in any way my production certificate once I rollback DNS changes.

Thanks in advance for your input!