Don't wait for the IRS, especially if you filed a return without including 25% of your income. However, as tax champ @rjs says, do wait until the IRS has processed your return.
The IRS adds penalty and interest for every month of unpaid tax. If you wait for an IRS adjustment, your penalty and interest will be higher than if you amend and pay your unpaid tax now.
To amend your return see How do I amend my 2021 return?
You should also contact IRS about penalty relief since it sounds like you made an honest mistake. For more info see Penalty Relief due to First Time Abate or Other Administrative Waiver.
