Vero and Vera sound nice and aren’t likely to cause confusion.

How about simply V?

Nika please.

How about sticking to Veronika? I still feel bad that People always and only use my nickname. Veronica has a lot of meaning: “Veronica is a female given name, a Latin alteration of the ancient Macedonian name Berenice (Βερενίκη), which in turn is derived from the Macedonian form of the Attic Greek Φερενίκη, Phereníkē, or Φερονίκη, Pheroníkē, from φέρειν, phérein, to bring, and νίκη, níkê, "victory", i.e. "she who brings victory".”

Nikki??

I had a friend named Violet that went by Vi, pronounced like vie. That might work for you? Aside from that I quite like Nika. I don’t think anyone would associate that with a slur.

Yeah nicknames are kinda picked for you, but I think you should always be allowed to say “my name is Veronika, but I go by ….”.

Personally I like Vera best because it's a unique name that sounds pretty. However, as someone with a long name as well, I just let my friends call me whatever they want so long as I agree with it. That's sort of how nicknames work; you don't get to choose but if your friends are respectful enough, you can approve of it.

Probably no use for you, but interesting nonetheless: In Bavaria, Germany, Veronika is shortened to "Vroni", with the v pronounced as an f and with the o spoken long (so, not short like in Ronnie).

“Ronnie” has a nice midcentury vintage feel, if that’s of any value to you one way or the other.

The main 'Veronica' I know from popular culture is from the Archie Comics (and more recently Riverdale) and was nicknamed 'Ronnie.'