"High net worth" work event - what to wear?

[Allwelcone]

I have to attend this in a major capital city, wtf do I wear? I will be on meet greet mingle duty.
I'm a tall size 14 mid 40s, can' only do small heels. "Helpfully" my budget is as small as possible.

I'd search Vinted for an LBD personally.
Groomed, statement necklace.

Ooh thanks @GlitteringUnicorn there's a max mara on vinted which might do. I guess just meld in to the background. Luckily it's beige!