The two big factors with that question are:

1. Movie or series?
2. Adapting an existing game or creating a new story?

Which makes the most sense to you and how would you want to see it executed?

I personally think that Zelda's already a series with so much room for creative interpretation, with an established history of consistently reimagining past games as new stories (ex: many story beats being shared between A Link to the Past, Ocarina of Time, and Twilight Princess), that it'd almost feel like a waste not to make a new story.

That's not to say that some game plots couldn't benefit from being adapted to a more narrative-driven art form, but The Legend of Zelda is already a series where every other game is treated as a new twist on the same legend, with alternate versions of the main cast being a dime a dozen each with their own backstories and novelties. I see no reason for an animated franchise to not go in the same direction.

They can bring back select pieces from older games, you know, locales, legacy characters, maybe even a MacGuffin or two, and they can certainly reference the series' history if needed in the same way The Wind Waker or Twilight Princess would reference Ocarina of Time in adventures that are mostly just doing their own thing.

But it'd be less restricting for the creators and more exciting for the viewers if they weren't bound to a specific interpretation of Hyrule and its cast, and were instead allowed to make their own. And hey, if this new story fits in the timeline in some way because it's all Nintendo-owned, all the better!

Whether it should be a film or series would depend drastically on how Link is portrayed and what kind of supporting cast he has. I think keeping him silent, or at least a man of very few words, is the right call to make, but how sustainable that is will depend on who's sharing the adventure with him, as well as whether or not the supporting cast will carry the weight of the main conflict more than Link himself (ex: Midna in Twilight Princess or Zelda in Breath of the Wild).

I'd personally pick a film first if there was a Hookshot to my head, but I'd have faith it could work either way if the series took reference from other films and shows with strong, mostly-silent protagonists like The Mandalorian or... I don't know, Jay and Silent Bob, then I'd be happy with either or.