How will a Roth Conversion from a Trad IRA affect 2022 AGI? (tax liability to be paid from a taxable brokerage account)

The amounts from your conversion as well as any gain from selling brokerage assets will be added to your AGI. You will pay income tax at your marginal tax rate on the conversion. Additional tax may be assessed if you sell brokerage assets at a capital gain—generally 15% but depends on your taxable income. 

Thanks.

How then will a Roth Conversion in an amount equal to the Standard deduction (or Itemized Deductions) affect the tax resulting from the amount converted?

Then you will owe tax on all your other income.   The Standard Deduction (or Itemized Deductions) is subtracted from your total income to give you the taxable income.  

Amount Converted would be considered an IRA Distribution (Other Income in TT Tax caster)?