Designer “after-wedding” dress

Hi! First time poster here. I am looking for a designer dress to wear post wedding out for the night in Las Vegas. I need something plus sized. Found a beautiful Versace dress, but afraid even the largest size wouldn’t fit me. I’m a size 16/18. Not super worried about the length but would prefer not a mini dress. I’ve googled til my thumbs are ready to give out and I live about 3 hours from the closest outlets that would allow me to try on these dresses in person. Max I’d like to spend is about $5k. Thank you for any help!

Pic of the Versace dress for reference.