Honestly, you have literally zero idea on almost most very basic items. You should just do some reading on Fidelity site to learn the basic knowledge.
The tax rates depend on a lot of factors - what is the tax bracket when you take the money is the most basic and the hardest to answer because it is an estimate in the future.
If you have decades ahead of you, then Roth would be the best choice since all profits earned are not taxable at the time you take money out from Roch. Regular IRAs the withdrawals are taxed as ordinary income.
Brokerage account it depends - short term gain is ordinary income, long term gain has some tax advantage, same also applies to ordinary dividends and qualified dividends.
You really need to read and learn, from Fidelity site and IRS site as the starter.
