After many iterations, trial and error using chatGPT, I wrote a js script to add all open tabs to favorites.
function OnClick(clickData) {
var cmd = clickData.func.command;
var tab = clickData.func.sourcetab;
var lister = tab.lister;
var allTabs = lister.tabs;
var favorites = DOpus.Favorites;
for (var i = 0; i < allTabs.count; i++) {
var currentTab = allTabs(i);
var currentPath = currentTab.path;
favorites.add(currentPath);
favorites.save();
}
}