If you’re looking to get a similar texture to whole milk, your best bet is probably an alternative milk with a similar fat profile to whole milk. That’s what makes whole milk the ideal milk steam so nicely. Many alternative milk brands will have a “barista” version of their milk that is intended to steam as nicely as whole milk. In my own experience, these have had much better texture than lactose-free whole milks, but you might have to hunt for a brand with a flavor that your gf likes.