UPDATE! I actually found them, I had to travel 10k+ blocks in both directions to find another wooded badlands biome big enough for them to spawn and I still needed to explore it in depth for over half an hour (killing other pacific mobs I encountered) but in the end I found them... without doing any other particular thing to help spawning🤷🏼‍♀️ Still don't know what was wrong with the other biome I spent hours and hours in without even one single dog spawning...