You use the openLight box and your dataObj would then be the data you want to pass to the lightbox.
So
let lightBoxData = { 'repeaterData': <the data to send> };
wixWindow.openLightbox("The Lightbox", lightBoxData);
Then when your lightbox opens, in your lightbox $w.onReady() function you need to have it get the data passed using the getContext() function.
Add this code to your lightbox page code
$w.onReady(() => {
let receivedData = wixWindow.lightbox.getContext();
let repeaterData = receivedData['repeaterData'];
});
Hope this helps