I don't think this plan makes sense. What will you do about the late credit cards? You'll need to pay them eventually, probably with that money you paid yourself first, except now there's additional late fees and interest.

Sure. General rule of thumb is no more than 1/3 of your gross pay, but obviously this doesn't make sense after a while. There'd be no reason for you to spend 66k/yr on rent for 1 person.

Would you be okay earning just above minimum wage your whole life? If not, you should formulate a plan to increase your earnings. A second job is the most straightforward way, but you could also look into a different line of work or trade school. You are young enough where these changes can have a massive impact on your total lifetime earnings and quality of life.

This is a pretty broad question and it depends on your risk tolerance. Furthermore, some investments are simply bad, regardless of your appetite for risk. What do you define as "high risk"? Like crypto? Penny stocks? Options?