For the underpayment penalty you can elect to to treat the tax withheld as paid when it was actually withheld. I don't understand?

[Opus 17]

The best thing to do is to decline Turbotax's offer to calculate a penalty, and let the IRS send you a bill after you pay the taxes.  The calculation is almost always off by a few dollars and you end up getting a bill anyway.

Plus, when you get the bill, you can apply for an abatement if it is your first time. (Interest can't be abated, though.)

Abatement https://www.irs.gov/businesses/small-businesses-self-employed/penalty-relief-due-to-first-time-penal...