The createRecord command expects a key of 'record type', whereas in the record class, the property is named recordType. Similarly, createRecord wants URL in all uppercase, whereas the class property is url in all lowercase. I think that this is a change introduced with DT4 (I’m sure of that in the case of recordType as that didn’t exist in DT3).
Example in the scripting dict for createRecordWith
(() => {
const theApp = Application("DEVONthink");
const theGroup = theApp.currentGroup();
let theBookmark = theApp.createRecordWith({name:"DEVONtechnologies", 'record type':"bookmark", URL:"https://www.devon-technologies.com", comment:"Our website.", tags:"DEVONtechnologies,DEVONthink,DEVONagent"},{in:theGroup});
let theNote = theApp.createRecordWith({'name':"Note", type:"markdown", content:"# Headline\n\nType your notes here."},{in:theGroup});
let theSheet = theApp.createRecordWith({'name': "Sheet", type: "sheet", columns:['Name#text','ID#uuid','Num#int'],cells:[['First','1','1.23'],['Second','2','4.56']]},{in:theGroup});
})();
(Note: The last two examples use type instead of record type – is that correct?)
I know that AppleScript doesn’t give a damn about casing, but JavaScript does. And it would be easier if property names and keys in the createRecord dictionary matched. In the case of record type vs. recordType, the former requires the key to be quoted, the latter doesn’t.
Also, addReadingList wants an all-lowercase url.