We received our 1099-B and turbo tax only asked for proceeds and cost basis which were big

The fact that your 1099-B reflected large numbers is not unusual if you did a lot of trading.  You can move the same money making trades over and over again.  this will make your cost basis and proceeds grow every time you use the same money to do a different trade.

Here's where you enter or import your 1099-B in TurboTax:

1. Open (continue) your return if it isn't already open.
2. Income & Expenses
3. Scroll to Stocks, Mutual Funds, Bonds, Other
4. Answer Yes to Did you sell stocks, mutual funds, bonds, or other investments in 2020?
   • If you see Here's the info we have for these investment sales, select Add More Sales.
5. Answer Yes to Did you get a 1099-B or brokerage statement for these sales?
6. At Let's get your tax info, choose how you want to enter your 1099-B (import or type it in yourself).
7. Follow the instructions.

 After entering or importing your 1099 B be sure to review the detail.  From time to time your broker does not know what your basis was (amount you paid for the investment), and it will be blank.  This will result in owing excess taxes.  You can be manually enter a correction.