Did I become unhappy b/c of this change? It's arguable. I'm sad that I can't play video games anymore but I'm happy to know that I'm interview ready at any given time, and can exercise my will to attempt to get higher salary jobs at any given time. So it's a give and take.
We don't have to, but we'll have less pool of jobs to choose from.
As for solving leetcode problems; it's just like a riddle. You become better at it the more you do, b/c you start to see a pattern. However, if you choke or don't get a question you solved before (or you solved before but can't remember) , better luck next time.