Get your taxes done using TurboTax

I would recommend taking this approach so that there is a clean paper trail reported in your return.

1. Enter the 1099-MISC exactly as received so the EIN and the $20,000 match the IRS records for "Prizes."
2. Now go to wages and income>less-common income>miscellaneous income>other reportable income
3. One you get to the description screen, you will describe this as "Reclassified to Gambling Winnings for Schedule A."
4. enter the amount of your losses as a negative number. (eg -20000)
5. Now go less common income>prizes, awards, and gambling winnings
6. Here you can enter your gambling winnings and record your losses. The winnings will now appear on line 8b in Schedule 1 and your losses will appear on line 16 on Schedule A.

Now to address your questions.

1. The answer to your first question is yes. it goes on Line 16 in Schedule A.
2. Yes, if you file by mail, you would not need to include a Tax ID number
3. As far as IRS correlating the numbers, maybe but we may be overthinking this.

In reality, you should have been issued a W2G but wasn't. The casino is not going to recant and send you a corrected W2G so this is the only avenue you can take to report this as gambling winnings and deduct your gambling losses. I can't say for sure if you will be examined for this but be sure to keep all your documentation for your gambling winnings and your losses in case if the IRS has questions.

@HelpMeLawd