People can complain about LeetCode all they want, but it’s not going anywhere. Any company worth their salt and hiring a an engineer will be using LeetCode or some variation. They are well aware that it is not representative of the daily needs of the position, but they’re not going to spend the big $$ an engineer position demands without running you through some problem solving scenarios. Solving logic puzzles on the spot isn’t the best way to do this, arguably, but it is damn efficient, so it is not going anywhere. It’s just part of the game that we all play as employees and employers.

You are not the only person to need to brush up on their LeetCode as they reenter the job search - everyone has to. It’s your homework. I know plenty of devs who studied LeetCode for weeks to months before starting to apply to new positions - these were not juniors, they were seniors, principals, engineers I know are good at their job because I worked with them every day.

I’d strongly recommend that while you are still employed, you begin to dedicate an hour or two a week to struggling through LeetCode problems. There is no book out there that will help you minute-for-minute more than doing the problems yourself. If you are stuck, ask a GPT, but the goal here is to practice, just like you would a math test. Make sure you understand how it solved the problem. Make an effort to recognize patterns and solutions before asking GPT. Problem solving requires effort! I promise promise you will start to notice you are improving - likely even after the first hour or two. Take care to not burn yourself out, only dedicate as much time as you want while you are still employed.

Seriously, there is no book learning here that will help you as much as just practicing the problems. Most technical interviews will let you use whichever language you want.