In my personal experience, finding the balance between hard work and fun is complicated, for this reason I created Dopaminite, it is a simple tool that helps you manage your time and improve your productivity. The way it works is very simple:
When the counter reaches 0 an alarm will sound ⏲️.
80% work, 20% fun
And that's it! I know it's very simple, but this reward system is helping me to be more focused when I am working, I hope it helps you too.