How to display a text element depending on a boolean value in a collection?

You just have to parse the repeater :

 $w("#repeater1").forEachItem( ($w, itemData, index) => {
 // Check the corresponding index in dataset
 $w("#dynamicDataset").getItems(index, 1) .then( (result) => { 
// Perform the check and hide/show (same code as above)
...