A 1099K is not like a 1099-INT or 1099-Misc. You do not need to report it on your tax return nor will the IRS question you for a small amount reported to you on a 1099-K.
There are new reporting rules starting in 2022, a lot of people are going to start receiving these.
Sportsbooks, including online ones, don't issue 1099s unless you win greater than 300-1 on a single bet, which is very rare...
Yes there is technically a paper trail when you bet online, but nothing gets reported to the IRS and you won't receive a 1099.