You can convert with $SYSTEM.Util.UTCtoLocalWithZTIMEZONE().

https://cedocs.intersystems.com/ens20141/csp/documatic/%25CSP.Documatic.cls?&LIBRARY=%25SYS&CLASSNAME=%25SYSTEM.Util

USER>write $SYSTEM.Util.UTCtoLocalWithZTIMEZONE($ZTIMESTAMP)
66263,48361.382728
USER>write $ZTIMESTAMP
66263,15968.3579578
USER>
 
USER>write $ZDATETIME($SYSTEM.Util.UTCtoLocalWithZTIMEZONE($ZTIMESTAMP),3)
2022-06-03 13:26:26
USER>write $ZDATETIME($ZTIMESTAMP,3)
2022-06-03 04:26:34
USER>

ImportDDL() method in %SYSTEM.SQL.Schema class can run multiple queries.

Documentation is https://docs.intersystems.com/irislatest/csp/docbook/Doc.View.cls?KEY=GSQL_import#GSQL_import_cache

Step1: preparing import file like below:

You need to use "go" in end of each query.  (c:\temp\updatequeries.txt)

UPDATE Test2.Person Set Name='abc' where ID=1
go
UPDATE Test2.Person Set Name='efg' where ID=2
go
UPDATE Test2.Person Set Name='hij' where ID=3
go

Step2: running  ImportDDL() method like below:

USER>do $system.SQL.Schema.ImportDDL("c:\temp\updatequeries.txt","c:\temp\import.log","IRIS")
 
 
Importing SQL Statements from file: c:\temp\updatequeries.txt
 
 
Recording any errors to principal device and log file: c:\temp\import.log
 
 
  SQL statement to process (number 1):
     UPDATE Test2.Person Set Name='abc' where ID=1
      Preparing SQL statement...
      Executing SQL statement...
  DONE
 
  SQL statement to process (number 2):
     UPDATE Test2.Person Set Name='efg' where ID=2
      Preparing SQL statement...
      Executing SQL statement...
  DONE
 
  SQL statement to process (number 3):
     UPDATE Test2.Person Set Name='hij' where ID=3
      Preparing SQL statement...
      Executing SQL statement...
  DONE
 
Elapsed time: .01458 seconds
USER>