Help find me a dress please

[Schwarmallama]

I have a black tie event in 10 days. Apparently it's got a "colourful" theme. All my posh dresses are black.

I am late 40's and an awkward shape - size 10, 5ft 5 but very broad and muscular. My shoulders and the tops of my thighs are my widest points. My hips are narrow and I have a high waistline and a pretty flat stomach at the front but my weight sits at the top of my hips and back. I tend to go for fitted clothes which flare at the bottom - so tight top and wide leg bottoms tend to suit me. I look like a brick in baggy clothes.

I am generally a none pattern type of person and tend to play it safe with colour. I might order this to try but I'm worried about the amount of back flesh:

https://www.becauseofalice.com/products/chiffon-plunging-cowl-neck-maxi-dress-abstract-pebble

Any other suggestions most appreciated.

Thanks

Is there dancing, because I want that glued to my front just in case...?😁Though it's lovely.
If you anticipate twirling on a dance floor something like this might be less worrying.
https://www.karenmillen.com/product/karen-millen-sequin-halter-neck-hanky-hem-maxi-dress_bkk29679?colour=burgundy&size=6

I would wear one of your existing dresses and go colourful with shoes, accessories, jewellery.

I doubt you are really very broad or a strange shape. Go for a fit and flare one colour dress that doesn't show a lot of skin.

Women's Dresses - Plain, Fit and Flare, Maxi | John Lewis & Partners

Alie Street Sophia Maxi Dress, Plum Wine
Phase Eight Klana Plisse Maxi Dress, Burgundy
Adrianna Papell Petite Tie Front Mikado Sleeveless Dress, Electric Pink
...

I'd wear something I already have - even though it's black