I did a side by side of about a dozen leather waterproofing products. Not super scientific but used offcuts of veg tan, applied as instructed, and took notes after spraying with water. In my opinion the Saphir super invulner was the best of those intended for nubuk/suede, and I liked Obenauf HD or Pecards for smooth leather, and duck back for canvas. But there’s about 400 products out there.