Perfectly described and I went thru similar “existential crisis”. I would build off of this and add that taking a job is NOT an admission of failure or defeat in accomplishing your life dreams and goals. You can take a job, and still work on your business on the side. You might be surprised at how well the company you work for can teach you about business and operations and marketing to augment your endeavors. Good luck!
im going to answer a different question to give you a broader perspective since you indicated that your driving motivation is finances (not a bad thing).
since its a small company and you’re the only dev, have you considered negotiating with the owners to become CTO and ask for partial ownership? i think the leverage you have is tremendous and you haven’t realized it yet.