Territories Health Equity Act of 2021 This bill alters provisions relating to the treatment of U.S. territories under Medicaid, Medicare, and Medicare Advantage. For example, the bill eliminates Medicaid funding limitations for U.S. territories beginning in FY2022, exempts an individual from late-enrollment penalties for Medicare medical services if the individual resided in Puerto Rico as of the date of eligibility and the individual enrolls within five years of such date, and establishes minimum criteria for certain elements used in Medicare Advantage payment calculations for areas within U.S. territories. The bill also allows residents of U.S. territories who are unable to obtain health insurance through their employer or a health insurance exchange to instead obtain coverage that is at least as broad as the coverage available to Members of Congress and their staff through the District of Columbia exchange.