What is life if you don't have fun?
The purpose of life is a very subjective and philosophical question, but having fun is an important part. If you don't have fun, you could try other activities that you like more. It could be that you are mainly pursuing things that you find boring or exhausting, which might lead to the lack of fun. You can try finding something you are passionate about and work on that field.
Where can I find things that I am passionate about?