in a routine or class, the line

ClassMethod ALine()
{
    quit $st($st,"MCODE")
}

gives you the line quit $st($st,"MCODE")

The systemvariable $zname gives you the name of the routine, where you reference $zname and in a classmethod $this gives you the name of the class

ClassMethod TimeDiff(inpTime = "2024-08-07 17:58:51.563")
{
	set current=$h // or $now(tz-offset)
	set inpTime=$zdth(inpTime,3)
	quit current-inpTime*86400+$p(current,",",2)-$p(inpTime,",",2)
}

First, I presume, the Studio lacks such a functionality because usually each nsp contains independent data. As an example, for each of my customers (applications) I have an dedicated namespace  (of course, you may say, one can allways have an exeption),

and second, if there is no readymade functionality, then make your own. Sometimes it takes longer asking questions or searching the internet then writing a quick-and-dirty "one liner", something like this:

// classdefinitions are stored in ^oddDEF, mac-routines in ^rMAC
// as said above, quick-and-dirty:
// if the SEARCHTERM occurs in %-items, then you will get multiple hits
//
// the one-liner version
k n i ##class(%SYS.Namespace).ListAll(.n) s n="" f  s n=$o(n(n)) q:n=""  f s="^|n|rMAC","^|n|oddDEF" f  s s=$q(@s) q:s=""  w:@s_s["SEARCHTERM" s," ",@s,!

// for folks with less experience
//
ClassMethod SearchAllNSP(searchterm)
{
   i ##class(%SYS.Namespace).ListAll(.n) {
      s n=""
      f  {s n=$o(n(n)) q:n=""
          f s="^|n|rMAC","^|n|oddDEF" {
             f  s s=$q(@s) q:s=""  w:@s_s[searchterm s," ",@s,!
          }
      }
   }
}

It's up to you to left out all those multiple %-items and to add some formatting...

So the bottom line of my answer is: yes, there is a way to search (whatever you want) in one go

set myObj={}
if myObj.%Size()=0 { write "This is an empty object" }

Class DC.BigJSON Extends %RegisteredObject
{

ClassMethod Test(filename)
{
	if ..SaveToFile(..MakeJSON(), filename) {
		write "Save OK",!
		write "Size ",##class(%File).GetFileSize(filename),!
		
		set input=##class(%File).%New(filename)
		set sts=input.Open("RS")
		if sts {
			set json={}.%FromJSON(input)
			set iter=json.%GetIterator()
			while iter.%GetNext(.key, .val) {
				write "key=",key," size=",$l(val)," data=",$e(val,1,10)_"...",!
			}
		} else  { write $system.Status.GetOneErrorText(sts),! }
	}
}

ClassMethod MakeJSON()
{
	set obj={}
	set obj.text1=$tr($j("",3600000)," ","a")
	set obj.text2=$tr($j("",3600000)," ","b")
	set obj.text3=$tr($j("",3600000)," ","c")
	quit obj
}

ClassMethod SaveToFile(obj, filename)
{
	set file=##class(%File).%New(filename)
	set sts=file.Open("wnu")
	if sts {
		do obj.%ToJSON(file)
		do file.Rewind()
		use file.Name 
		do file.OutputToDevice()
		do file.Close()
		quit 1
	} else { quit sts }
}

}

The size shouldn't be a problem

USER>do ##class(DC.BigJSON).Test("/tmp/test1.txt")
Save OK
Size 10800034
key=text1 size=3600000 data=aaaaaaaaaa...
key=text2 size=3600000 data=bbbbbbbbbb...
key=text3 size=3600000 data=cccccccccc...

If your system does not support JSON (i.e. pre 2016.2?) then give this "dirty trick" a try:

- add a zero-width-space character to your numbers
- create the output stream
- remove the zero-width-space characters

Instead of the zero-width-space you can use any other character too, which does not appear in your data (binary data should be base64 encoded).

ClassMethod WithQuotes()
{
	set zwsp = $c(8203) // zero-width-space
	set obj = ##class(%ZEN.proxyObject).%New()
	
	set obj.ID = 1234_zwsp
	set obj.Number=123.45_zwsp
	
	if ##class(%ZEN.Auxiliary.jsonArrayProvider).%WriteJSONStreamFromObject(.tmp,obj) {
  		set json=##class(%Stream.TmpBinary).%New()
		do tmp.Rewind()
		while 'tmp.AtEnd { do json.Write($tr(tmp.Read(32000),zwsp)) }
	}
	
	do json.Rewind()
	write json.Read(json.Size)
}

In the above code just insert a Lock and Unlock, and the problem is solved

  //Buid table if it doesn't exist
  
  lock +^LockOutOthers // or any other name you wish
                       // No timeout! At this point everybody has to wait
                       // as long as the current job does a table check/update
  &SQL(
  ...
  ...
  }
  
  lock -^LockOutOthers  // let the others in
  
  Quit outVisitID
  

Just came to my mind
- Cache-5.0.x is likely to be 32 Bit version, Win-11 is 64 Bit (only) (in case, the application uses some .dll, .ocx, etc.)
- unlikely that you use it, but as a hint, LAT is not supported anymore
- user database is now provided by ISC. In case your application maintains its own users, you can still use your own user database, but the login process will require some "adaption"

As a first step, I would contact your ISC Sales because Cache-5.0.x licenses neither work with (the latest) Cache nor with IRIS. Second, there was a lot of change between Cache-5.0.x and recent Cache/IRIS versions, so I would check to see if there are any problems to expect. A customer of mine "upgraded" fom Cache-5.0.21 to IRIS  some four years ago...