No specific dress suggestions, but I’ll put in a good word for Nordstrom. I ordered multiple outfits from them to try on at home then returned all but three. One was for the rehearsal dinner, one for the ceremony and the third for the reception.
Another store you might not think of is TJMaxx. I’ve continued to see several long gowns on their website each time I’ve looked. They’re often the same brands and styles that I’ve seen at department stores but at a pretty good discount. Returns are not as convenient as with Nordstrom and there are far fewer choices, but you might get lucky.