American Broadband Buildout Act of 2021 This bill requires the Federal Communications Commission (FCC) to provide matching grants to help states improve broadband infrastructure. The bill requires the FCC to distribute matching grants for state-led, public-private partnership projects connecting areas where internet service is not available above a certain speed to broadband infrastructure. As part of these projects, the bill also requires the FCC to award grants for digital literacy programs and public service campaigns designed to increase adoption of broadband internet access and service.