I should be able to deduct whatever percent of the fees that the taxable portion of the SSDI amount is. I've spent a lot of time looking for a place to enter it, but can't find anything.
For federal income tax purposes, legal fees are no longer deductible. The Tax Cut and Jobs Act of 2018, disallowed miscellaneous itemized deductions for the period 2018-2025. That includes personal legal fees, including legal fees incurred in the production of taxable income. i.e. Social Security.
However, you may include them and TurboTax will transfer the amount as a deduction on your state income tax return, if your state allows it.
To enter:
In general, only legal fees that are related to your business, including rental properties, can be deductions. This is true even if you didn't win the legal case in which the legal fees were incurred.
The information below, was taken directly from the Turbo Tax search questions. It seems to be one of the few legal fee deductions you can still take. I can find no place to enter this, where it counts as a deduction. If entered under "Legal Fees", it won't be counted as a Federal deduction. It just gives a message that legal fees aren't deductible under Federal taxes, but will be used for State tax purposes.
You can deduct the percentage of legal fees related to your Social Security benefits that are taxable.
@HelenC12 gave you perfect guidance. That information applies to both 2020 and 2021.
As stated, The Tax Cut and Jobs Act of 2018, disallowed miscellaneous itemized deductions for the period 2018-2025.