I've heard this pronounced "wah-la" or (waa-la) in the USA (without a "v" sound).
Even on TV! ;-)

I always say "voi-là", with the "v" not "w". Like the French. I know this sounds silly, but in the USA, I frequently hear people say it with a "w" sound.

Is this regional? US, UK, or otherwise? Dictionaries typically recommend a "vw" sound.

Here's MW:
Main Entry: voi·là
Variant(s): or voi·la \vwä-ˈlä\
Function: interjection
Etymology: French, literally, see there
Date: 1739
—used to call attention, to express satisfaction or approval, or to suggest an appearance as if by magic

Here's CALD:
voila exclamation
/ˌvwɑːˈlɑː/
used when showing to other people something that you have just made or got and are pleased with
Corn tortillas can be cut into strips, fried until golden, and sprinkled with salt - voila! tortilla chips.

Here's B/W:
Aus: WAHRIG Rechtschreibung
voi|là [voala, frz.] sieh her!, sieh da!, hier ist …!
Aus: BERTELSMANN Wörterbuch
voi|là! [voala] sieh her!, sieh da!, hier ist … (zu sehen)! [frz., zu voir ”sehen“ und là ”(dort)hin“]

But I guess B/W wouldn't count ... well since ... it's not the English pronunciation.

OT: I'm surprised it isn't an official Leo entry (voilà) -- discussions not necessary about that translation. 1:1. ;-) It makes me wonder what other French words are a 1:1 translation between English/German, but there are likely dozens of threads on that topic.