Presidential Allowance Modernization Act of 2023 This bill replaces provisions governing the compensation provided to a former President. Each former President shall receive from the United States (1) an annuity of $200,000 per year for the remainder of his or her life, and (2) a monetary allowance of $200,000 per year. Such allowance shall be reduced by the amount the former President's earned income exceeds $400,000. These monetary amounts are subject to a cost-of-living increase. The bill increases and provides for cost-of-living adjustments to the monetary allowance for surviving spouses of former Presidents.