Should I report capital gains if I reinvested and did not withdraw?

Simple answer: Yes.

If you have a taxable (not an IRA, 401k or similar account)  brokerage account and you sell stocks or mutual funds, you have "realized" a gain (or loss) and it must be reported on your tax return, even if your didn't withdraw the money form the account. 

Yes, taxes are paid on when you sell the securities at a gain, regardless of whether you withdraw it or not. However, if those gains were made in tax advantaged accounts like IRA or 401(k), you may not have to pay taxes on those gains.

Additionally, you should have received Form 1099-B from your brokerage company which shows the taxable gains you made in 2021. You will need to enter that Form in TurboTax so that your return is accurately reporting all the income.