If you’re getting 0 interest you’re just letting the bank rip you off because they’re just doing reverse repos at the fed or buying T bills and earning risk free 5% with your deposit and giving you nothing. You don’t have to invest in anything risky, you could buy t bills from treasurydirect or you could buy an ETF like USFR that invests in short term treasuries. The only risk is that you’ll have to wait 2 days for your funds to settle once you sell and transfer back to your checking account, although there are some brokerage investment accounts that give you access to a debit card that you could use like a checking account.