Secure Rural Schools Reauthorization Act of 2021 This bill extends through FY2023 payments made to states and eligible counties containing certain federal land under the Secure Rural Schools and Community Self-Determination Act of 2000. The Department of the Interior and the Department of Agriculture shall carry out a pilot program to allow the Chief of the Forest Service or the Director of the Bureau of Land Management to nominate members of resource advisory committees. County funds may be used to provide or expand access to (1) broadband telecommunications services at local schools, or (2) the technology and connectivity necessary for students to use a digital learning tool at or outside of a local school campus. Any county funds that were obligated by a county before October 1, 2017, but are unspent on October 1, 2020, may be used by the county for any authorized use and shall be available for projects initiated after October 1, 2020. No county funds may be used for lobbying activity, regardless of the purpose for which the funds are obligated on or before the enactment of this bill.