The problem is fixed. Now, I can use Visual Studio 2022 to connect to Big Data in Stratus, and I can use queries to browse data in Big Data.
I believe the key is to click "Rebuild Data" button, and then wait for one hour for data to be synchronized. I might not have waited long enough for one hour for the data to be synchronized.
As long as I got Server ID, Database ID, and SQL User and Password, I can connect to Big Data.
Liz Fong from Stratus helped me with this one - especially the "wait one hour requirement".
jaysomlam