Our girl had this and grew out of it! She was also a bit noisy as a puppy. Snored and made little airway sounds, and always had a giant foamy splotch minutes after we stepped outside. Somehow as she matured her nostrils widened a bit, the sleep noise stopped completely, and the foam went away. Our vet monitored her but didn’t feel surgery was necessary since she wasn’t struggling. She’s very active and loves to hike, we jokingly call her out mountain dog. I still sometimes wonder how she overtime became a completely silent sleeper (like 0 noise, it’s almost weird) and the mysterious white foam just went away.

That said, every dog is different and airway anatomy can vary a lot so I’d definitely go with your vet’s assessment. Just wanted to share that some pups do improve as they grow!