Hi Juraj,
Thanks for your response! I have read related docs to know that the Ultimate license doesn't support the "Web farm" feature.
When I try to configure the Content Staging, it doesn't display the "Servers" tab within Staging application as doc mentioned.
https://docs.xperience.io/deploying-websites/content-staging/configuring-content-staging#Configuringcontentstaging-Configuringthetargetservers
So I assume we can't use the Staging feature with the Ultimate license. The document mentions that we need to choose a server or create a new server, but we are not able to see those options.