I was in burnout pretty bad while working for a big bank in my country. The work was very stressful, lots of office politics even though they paid pretty well, and my boss were nice (with a lot of pressure lol). I just thought I was not a good employee because I was tired all the time, then I started my company. My gosh, the work was (and still is!) 1000 times longer, harder, everything is so so bad and need addressing all the time YET I am no longer feel burnout for a few years now (since I started my company). For me, the burnout is not related to the workload or the complexity of the work--you need to ask yourself a question: why are you doing what you are doing? Is it what you want? Otherwise you will always in burnout until you find your mission in life.