Black tie outfit, for a non-heels wearer

[ChatHRT]

I am attending a formal black tie meal followed by dancing.
I would love to wear a fabulous dress, but I can't wear heels (too uncomfortable) and I find they don't look so great with flats.
I live in trainers and wellies
I am a 10 but verging on 12 up top due to big boobs, athletic figure with a bit of menopausal middle weight. 5'8
I don't want a jumpsuit, looking for a tuxedo suit, but worry about looking like all the blokes (v make heavy industry).
Any suggestions?

I think flats are fine with floor length dresses, would that length be too formal?

Full length would be ok, I just fancy something a bit less ordinary
Phase eight & coast are not exciting
Looking for inspiration, budget up to £150 (not incl shoes)

What about some chiffon (lined) wide legs pants that would look great with a similarly soft top, or sequined top, with a more tailored jacket or an 'opera coat' in a satin finish on top. I say this because this was part of my mix and match wardrobe when I went to a lot a lot formal work events. I also had a matching skirt to my jacket, a variety of tops and a couple of dresses that went underneath

If you are near one, I got most of it from Boundary Mill, but there are similar outlet malls.

I think you can wear any dress really, as long as you keep the flats dainty and dressy. Perhaps slingbacks with a pointy toe.

Thank you @ForPearlViper I will Google that style, sounds interesting

How about a velvet tuxedo?

You can go wow with a printed one (Boden via Vinted)

Or go for a red/pink one to stand out?

Or black/navy with a colourful silk shirt - jacket off for dancing (sparkly metallic trainers or flat pumps?)

 this Reiss blazer with either the trousers she has listed

(I am looking at Vinted already - assume there are versions of this in the shops for first hand)