You can't claim the $300 above-the-line Charitable Deduction in addition to the amount claimed if you itemize.  

If you Itemized your Charitable Deductions are included in Schedule A .

The Cares $300 Charitable Deduction is only available if take the Standard Deduction.

Taxpayers who take the standard deduction can also now write off up to $300 in charitable cash donations in 2020 regardless of filing status. This increases to $600 in 2021 for married filing jointly. This is a new "above-the-line" deduction for people who claim the standard deduction.

No I'm not.  The problem is if I itemize I have 12,522 in total deductions.  If I take the standard deduction I have 12,400 + 300 Charity.  The Std Deduction is the better option, but TTax is recommending Itemized. 

You do not have to itemize, you can take the standard deduction.

Just revisit Deductions & Credits and after it offers Itemized Deductions as the preferred choice, just click the box Change my deduction.  Then change to Standard Deduction.