I have no idea where to shop anymore! Where can I buy a dress for a birthday party with a "polished cocktail" dress code?

Hello all!

Usually it is I dispensing brands and advice like a fashion goddess but today I turn to you :)

I'm seeking cocktail gowns/occasion dresses.

Here's my requirements:

Size 14/16/XL

Available in US, by April 1 at latest

Prefer voluminous, midi/maxi length (not short, tight, body con stuff)

Color preferences are soft tones like seaglass, sage green, lemon yellow, lilac, etc. Metallics okay. Black okay but not preferred.

Would love something that feels 60's in nature, a little artsy and playful

Jersey is too casual, same with printed chiffon stuff

Budget is up to $250 for the perfect dress

Balance between structure and flow, so no kaftan "gowns" but also no ultra tight sheath dresses

I'm seeking a knockout dress, one that will make people stop and go "wow! I love that dress!"

This is an example of a playful, structured but interesting dress that I loved but ultimately it's not my color and it feels more business than pleasure

I also considered this dress but...feels a tiny bit too casual to me

Many occasion dresses marketed to older ladies feel very mumsy and MOTB and aging to me, while the selection overall is either very bar hopping 20 something in a short, tight skirt OR "Madame President attends the Oscars". Also many of the most suitable and gorgeous dresses are either sized out for me (like stop at a 12) or are $$$$ much more than I feel comfortable spending on an occasion gown

Like this STUNNING $800+ gown wow, everything I want in a dress, and it's just shy of $1000 sob.

AnyWAY: lay it on me! Give me your fun, cool, dazzling cocktail dresses for me!

EDIT:

I found a possible and it's on order, will report back when it arrives! This Theia dress thank you alert reader

Update: The dress was too small, sadly, with no possible way to make it work (like shapewear, etc). There is a size 16 available..for $495 on the Theia website which is a no go for me!

So I'm going with The Anthropologie Hutch Rosario for one night, and

Tadashi Shoji sequin dress for another night.

I have a third night scheduled and I don't really have a dress yet--I have a backup cute cocktail dress from SL fashions that's similar to the Tadashi Shoji one This dress in black I actually bought this in white as a possible wedding dress so I know it works but it's so close to the black dress that I'm very "eh" on using it. I'm currently surfing Macy's for a possible pick up curbside tomorrow or Thursday (we leave Friday), but our destination has TONS of amazing shopping so worst case I'll pick something up there.

Thank you u/pritheeanon!