I totally agree with you, as I am in the same situation. I am however slightly ahead of you in the process (end of 20s). Right after graduation I chose the first option you said ("maintaining a steady lifestyle and income by seeking well-paying jobs in the tech industry"), but beside getting better at programming (mastery) the latter two benefits (autonomy and purpose) are not fulfilled.
So I quit my job just two months ago with no immediate plans, hoping to enter the startup world, or pursue other dreams outside programming. I am as clueless as you are at this point, but one thing I can tell you is that seeking a well-paying job to begin with post-graduation is not all bad. You are young and you have time, and money in the bank helps A LOT when you are in my shoes. Having to worry about your account/juggle part-time jobs/living with your parents is no fun.
On the other hand, I would also like to hear what people ahead of me have to say as well. Should joining a startup be the first thing to do post-graduation? What did you do when you were not quite sure where your purpose was?