are you claiming you are a professional gambler? only a professional gambler can report winnings and losses on schedule C. if so, your gross income requires you to file because losses don't count in figuring gross income for filing purposes.
here's a link to the criteria the IRS applies in determining whether you are a pro gambler
https://www.journalofaccountancy.com/Issues/2012/Apr/20114684.htm
if not, then the $20,000 is reported under other income (schedule 1) and the losses go on schedule A which will only benefit you if you can itemize
