Duplicate and increment a file in Finder

My workflow involves duplicating project files in Finder and incrementing the number in the name each time there is a significant new version. This workflow is the same regardless of whether the extension is .ptx .mp4 .prproj etc

Example filenames
ProjectName-Mix-v1.ptx
ProjectName-Mix-v2.ptx

My script works OK so far, but it gives errors sometimes. Specifically sometimes it doesn't find the "Paste" menu item, and sometimes the script seems to happen too quickly and Finder gets the numbers wrong, or opens the old file instead of the new one. I have some manual "waits" in there but I was wondering if there was a better, more elegant and robust way of doing it.

Also I'm looking for a way to take my original file, and move it into a folder called "Old", and then to re-select the newly incremented file and open it (end of script).

And lastly currently it doesn't work if the file does not yet have a version number; not sure if there's a way around that.

Here's the script so far.

// Get name of selected file
var sourceFilePath = sf.ui.finder.firstSelectedPath;
var sourceFileName = sourceFilePath.replace(/^.*[\\\/]/, '');
var sourceFileNameQuoted = 'Copy “' + sourceFileName + '”';
var sourceFileNameNoExtension = sourceFileName.replace(/\.[^/.]+$/, "");

//Get and Increment Last Number
function getAndIncrementLastNumber(str) {
    return str.replace(/\d+$/, function (s) {
        return ++s;
    });
}

var destinationFileName = getAndIncrementLastNumber(sourceFileNameNoExtension);

// Copy selected file
sf.ui.finder.menuClick({
    menuPath: ["Edit",sourceFileNameQuoted],
});

sf.wait({
    intervalMs: 300,
});

// Paste file
sf.ui.finder.menuClick({
    menuPath: ["Edit","Paste Item"],
});

sf.wait({
    intervalMs: 300,
});

// Rename
sf.ui.frontmostApp.menuClick({
    menuPath: ["File","Rename"],
});

sf.keyboard.type({
    text: destinationFileName,
});

sf.keyboard.press({
    keys: "return",
});

// Open new file with default application
sf.ui.finder.menuClick({
    menuPath: ["File","Open"],
});

// Move original source file to folder called "Old" (in the background)
// Create folder if it doesn't exist