Here is one to think about
is it worth a long-distance haul?
I know it would add to your budget, but maybe it's worth haunting the sales sites for a different region where dressage is much more prevalent. Keep your radius to where shipping would be $800 or so, and line up a bunch of horses where you could fly in and try them all in a 2-3 day timespan. Or, hook up with a trainer in one of these areas who does consignment. Show them some vids of you riding so they have a sense of where you're at, so they could suggest good potential matches.
I totally get that it feels different and probably scary when it's entirely on you to CHOOSE a horse vs making it work with the one that fell into your lap. Just remind yourself how successful you've been with making it work with those other horses, and the love you developed for them. They weren't perfect, but they became what you needed, and vice versa.