I'm not sure when you last checked, but you can add songs either next in the queue or at the end of the queue when shuffling songs. I've just tested this on iO

I'm not sure when you last checked, but you can add songs either next in the queue or at the end of the queue when shuffling songs. I've just tested this on iOS 12.2. While you can't swipe to queue, you can force-touch on a song to bring up the quick menu, and then release over 'play-next'. A different gesture, but still a single gesture/tap.