I played both. Both are excellent games, and both also have flaws.
I think Zelda was by far the better game - HL isn’t really on the same level as it at all, design-wise, story-wise, or or in terms of things to do.
HL’s strength is definitely the world itself - the Hogwarts and Hogsmeade areas in particular are both incredibly well done and very faithful to the source material. The other areas are just alright.
I’d say HL’s weaknesses become most apparent if you’re a completionist. Things can get very repetitive if you’re going for 100%. I did, and I honestly think you’ll like it a lot more if you just don’t.
It’s still lots of fun though. Zelda was my most played game in 2023 and HL was kind of far behind, and everything else combined would still probably be a distant third.
I absolutely agree with the other people saying HL is generic and propped up by the IP. But for me that was enough.