Just poking around and I think, if you're willing to compromise on some things there's lots of options for you.
The thing that makes a lot of wedding dresses so expensive is lace or other labor intensive details, and layers.
My dress had like 4 skirts effectively. That's a lot of material. But you can easily get the illusion of a lot by getting a belt, a shawl, or even just finding a tailor and adding material over a more simple dress.
Now, I'm just looking on Amazon with these examples. But consider also looking at non-wedding dresses elsewhere or even back at DB, bridesmaid dresses or prom dresses to save some cash. Also consider poking around thrift stores or Goodwill.
Polyester, sure, but what a stylish cut!
Simple, long sleeve maxi. just throw a sparkly belt on.
Sexy without being too sexy, bodycon peplum midi. A pill hat or blusher veil would complete it!
Sparkly pink alternative to white.
Flowy and elegant off the shoulder
A peasant style for those fantasy vibes
just some that I found with a quick search. I hope that helps, or at least gives you some ideas. Any dress can be a wedding dress. And no one really mistakes anyone else for the bride despite many people worrying about not feeling 'bridal enough'. You'll be bridal because you're the bride, and the accoutrements do a lot of the bridal-feeling heavy lifting.
Also congratulations!