Zelda is one of those things I somehow missed growing up. The only one that I ever sunk any significant time into was Phantom Hourglass. It was pretty good. I've tried some of the other ones but I get the sense that they are hard to enjoy if you don't have nostalgia goggles on.
I tried BOTW. The story felt very uninteresting. Like nothing that was happening felt justified. And the gameplay just felt like Just Cause but without all the cool stuff to interact with.
BotW ruined the series. Open world, despite the promise of freedom, is a crippling set of shackles on world design. No upgrade can meaningfully interact with the world because every area has to be a potential first area. There's no mystery of "what's past this obstacle?" because everything has to be passable as soon as you see it. Worst of all, your reward for thoroughly exploring and completing all the optional quests? Butchering the final boss, which at full power is a highlight of the game, into the worst anticlimax of the series by removing multiple entire phases and drastically nerfing the HP of the phases that remain. The only intact phase literally can't hit you if you just run in circles around it.
All of this wouldn't be too bad if it was a one off, but Aonuma confirmed it's the template for the series going forward. We'll never see another proper Zelda game.
Breath of the Wild removed pretty much everything that made the series great. It leaves behind a meh game with some of the lore Nintendo knows will sell units.
Oof. Yeah, if you've only played Phantom "go back to the same temple for the tenth time" Hourglass and Breath Of The Wild with it's almost non-existent story, I can absolutely understand the disappointment.
Phantom Hourglass was pretty disliked even by fans at the time. The touchscreen control focus and the damn ocean temple re-runs were quite contreversial.
Breath of the Wild was the series's first attempt at open world, non-linear gameplay and is incredibly different from other games in the series. Very light on story and characters. Unfortunately they've confirmed open world is the planned standard going forward.
The real "core" 3D games are Ocarina of Time and Twilight Princess. For 2D, A Link To The Past and Link's Awakening.
Twilight Princess is probably the most accessible for someone not super familiar with the franchise, and the least burdened by old school design decisions. It's what I would consider the pinnacle of classic 3D Zelda. Took all the good stuff from the two N64 games (what most people seem to think are the best) and polished the hell out of it.
Actually I did enjoy what little of Windwaker that I played. But I played it on an emulator and had to wipe the machine it was on so I never got past the beginning.