If happiness is important to you…
Lower your expectations for the outcomes you get in life.
This does not mean you become a lazy donkey and waddle around in a pit of inactivity.
You should set goals for what you want to achieve. You should take action. But you should not expect results by comparing with other more successful people.
Recognize the role of luck in life and let go of the final result you get for any of your goal. Just focus on the action part and brush off whatever result you get.
Do not be attached to success, and do not mind failure. Both are transitory.
Have fun in the doing part and the “done” won’t matter.