For VS Code's native Search facility to search the server-side code your ISFS workspace gives you access to you must follow the instructions in the "Enable Proposed APIs" section of the extension's README (which is also available here). One of the steps will have to be repeated each time your InterSystems ObjectScript extension gets upgraded from MarketPlace with a new version.

my guess that if we specify port 57772 as the default port in the web server which I'm assuming that would be Apache , we don't have to specify the port in our url

No, if the web server (Apache or any other server) is listening on any port other than 80 (for http protocol) or 443 (for https protocol) your URL needs to tell the client app (e.g. your web browser) to connect to a port that is not the standard one for the specified protocol.

Besides the above, I also noticed that the parser also fails when calling a %SYS routine as in:

do DecomposeStatus^%apiOBJ(sc,.err,"-d")

@Victor Gordillo please clarify what you mean by "the parser fails". Maybe with a screenshot?

InterSystems deletes the source code of many %-routines before shipping, including %apiOBJ. Perhaps this is causing the problem you are seeing.