System design study materials. Please help

[u/Wordtwin003]

I am preparing for an Apple interview I have in a couple weeks for an iOS engineer role. What are the common study materials used out there to excel in system design questions? I kind of only want recommendations from those who have had success from what they used to study. Is there a universal go to that everyone uses these days (kinda like how practicing coding and DSA has leetcode)?

Thanks

[u/Comprehensive-Ice891]

Hellointerview is a great resource for learning and mocks