I like the first two because of their specific focus on dressage; the other two take a bunch of technical and mental filtering to get to what you want. On the other hand, it can be entertaining to spend an hour in the evening scrolling thru all kinds of horse ads.
I would also put the word out to trainers in your geographic range. They may have or now of horses to fit your need. I wouldn't rush off to Europe just yet; you should be able to find quite a capable horse here. And between your trip over and the trip back for a horse, you can add $10 -$15k to the cost.
We don't get less brave; we get a bigger sense of self-preservation........
Talk to Heidi at Villa Rosa Dressage. We bought a horse from them a few months ago and it was a fantastic experience..they are super honest, knowledgeable and helpful and they seem to have quite a few nice horse for sale.