My two cents: Focus on your health first. If you're not taking care of yourself and exercising, you're doing yourself a disservice mentally. Second, be disciplined when managing your time. Put in the hours you need to put in at work, but don't rob yourself of your free time by working excessively long days. If you want to improve your knowledge of CS, I'd recommend signing up for some courses. Online courses work but if you have a community college nearby that offers CS, I'd choose that. Having a place to go and meet other people with the same interests as you will give you a small social outlet and keep you accountable.
Random other thoughts: Leetcode sucks. Think of Leetcode problems as riddles. Most riddles are impossible to solve if you haven't heard them before.
Satisfaction in a career can come from many places. For some, it's all about solving complex technical problems. Others are happy to be contributing to a charitable mission. Some just want to get paid a lot. Others find satisfaction in being part of a team. Figure out what satisfaction means to you and align your career with that.