The problem isn't about doing like that small job and showing it that way, but it's like when it's not even allowed in your country (illegal let's say) but you still do it, they'll definitely get you and make you either pay a hefty sum to save yourselves from their trap or get trapped. It's about how you manage to take your money out of it.
Doesn't really matter as even if the name doesn't flash anywhere, the gambling companies that abide by a state's rules are definitely going to give the details of all the trades/deals/bets they go through. So you'll be caught there. If you try hiding it with crypto, then too you'll eventually need to pay taxes on your capital gains through crypto.