I’ve been using FreeTaxUSA.com tge past few years. Only the federal is free, state taxes are 15$ per, plus there’s a bunch of extras they try to get you to tac on, but as long as your taxes are simple and you’re not expecting to have something that may trigger an audit, they’re plenty enough.
Are you super sure that nobody else knows it? Why don’t you tell me so I can check for you if anyone I know knows it.