(I shouldn't have looked at the site though. One of the featured dogs is just my kinda guy - 'Jacko' the almost blind collie. If it weren't for Robin, I'd be on the next plane to the UK...)
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But back to Higa's search:
Higa, as your experience seems to show, available dogs go fast these days.
Ennui's suggestion may well be your best route forward - start getting to know breeders, even those who do not have pups now or litters planned. Good breeders typically want to get to know potential buyers well ahead of time, and then keep waiting lists for upcoming litters.
Also, do expand your search as far as you realistically can travel to a breeder or rescue. It is estimated that more than half of all dogs in Switzerland came from abroad, so looking farther afield is perfectly normal. But as you look abroad, do make sure you understand current import regulations. If you need any help there, just ask.
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One more group to keep an eye on: Retriever In Not/Liberty for Dogs, in Germany:
https://www.retriever-in-not.de/notf...uendinnen.html
Yes, I know you are not looking for a retriever. But this group not only focuses on the retriever breeds, they also help dogs 'retired' from breeding mills. As such, they tend to have small fluffies in with some regularity, as the sad truth is that these breeds, due to their popularity, are often victims of the Dark Side.
Many of the retired breeding dogs have been assessed as needing to go to homes with a resident calm dog, due to the baggage the industry inflicted on them, and so might not be appropriate for you. But not all. So keep an eye out from time to time, perhaps there might be one who would be a good fit for you.
And lastly - a lot of rehoming activity takes place on Facebook. I personally hate this approach due to all the drama and time wasters and bad faith, but I'm a dinosaur. If you are active on FB, I'm sure you can find those groups. But at the risk of sounding like a broken record, due diligence. It can be hard to spot the bad actors.
Again, wishing you all the very best.