The fiduciary (executor in this instance, most likely) should have provided you with a statement concerning the deductions and the code on your K-1 may actually be wrong.
if you need to enter any final year deductions on Schedule A of your return note the following:
If this is the final return of the estate or trust, and there are excess deductions on termination that are non miscellaneous itemized deductions reported to you as a beneficiary, you may deduct the excess deductions shown in box 11, code B, on the applicable line of Schedule A (Form 1040). The fiduciary will provide you with a statement of allowable deductions. See Final Regulations - TD9918 for examples of allowable excess deductions on termination of an estate or trust. A beneficiary who doesn’t have enough income in the tax year to absorb the entire deduction can’t carry the balance to any succeeding year.
Note. Section 67(g) suspends miscellaneous itemized deductions subject to the 2% floor for tax years 2018 through 2025. Therefore, miscellaneous itemized deductions are not deductible as excess deductions on termination. Consult your state taxing authority for information about deducting miscellaneous itemized deductions on your state tax return.
See https://www.irs.gov/pub/irs-pdf/i1041sk1.pdf
