#2 Question: Will the higher rate apply to all of my income if I actually make enough money to be in a higher bracket?
Bear in mind that the higher rate only applies to those who earn enough money to be in the larger bracket. Additionally, tax brackets can vary a lot depending on the filing status. However, one thing is certain: if your income goes up, the tax rate will do that as well.
For the 2020 tax year, you most likely paid 10 percent on the first $9,875 you earned as a single filer, 12 percent on income ranged between $9,875 and $40,125, and 22 percent on income between $40,125 and $85,525.