I'm not a CPA, but I have researched ROTH IRA's and backdoor options, etc. Basically you pay taxes on anything going into the ROTH upfront and anything you make is NOT taxable. However it must be in there 5 years before withdrawal, with a few exceptions.

You can find your answers here:
https://www.rothira.com/

https://www.rothira.com/roth-ira-withdrawal-rules

https://www.rothira.com/what-is-a-backdoor-roth-ira