Follow the path you took the first time. You have to take the aeronautical knowledge test again. As your background check is already done, if you haven’t done anything bad in the last two years there’s very little follow up to be done for the next check. And they do check.
Look at it this way, if you were doing a full scale biennial review you would be visiting a flight instructor for both an oral and written exam that would be followed up with an in flight proficiency check. You would be out of pocket somewhere between $300.00 and $800.00 and a full day or more of time. There’s also a medical exam every couple years for most unless they are flying a limited class. If you failed any of it you would be grounded until you passed. If we fail we just go fly as an amateur.