Yeah, it's really easy to get overwhelmed by the raw amount of stuff to study. I found I just needed to be consistent, and get through 3-5 leetcode problems a day, while trying to force myself to hit the problems in areas I was weaker. If I tried to enumerate everything, I quickly became very overwhelmed like you describe.

I think if you hit a balance of problems that touch on arrays, strings, linked lists, trees, graphs, stacks, queues, heaps, and also some dynamic programming you'll be good to go. I found that companies really love to ask graph problems in disguise, and once you know how to recognize them and the basic DFS/BFS implementations you're golden. And if you get good at graph problems, trees and linked lists are simple, so I think it's a great area to put extra focus.

I found the dynamic programming problems particularly hard for my brain to grasp, and I had to spend a lot of time repeating the basic problems and slowly building up my skillset. A ton of practice, and I never even got asked a single DP question in all the interviews!