Add the Canada benefit and the US Social Security benefit together and report on Box 5 Net Benefits for 2023.
The Canada social security equivalent benefit is explained in IRS Publication 915, page 6:
Under income tax treaties with Canada and Germany, social security benefits paid by those countries to U.S. residents are treated for U.S. income tax purposes as if they were paid under the social security legislation of the United States.
In other words, if you are a U.S. resident, enter your Canadian benefits as though you had received a Form SSA-1099 from the Social Security Administration.
Follow these directions.