Stopping Home Office Work's Unproductive Problems Act of 2023 or the SHOW UP Act of 2023 This bill reinstates the telework policies that were in place at all executive agencies on December 31, 2019, and requires each agency to submit a certified telework plan to Congress before such policies can be expanded. The bill requires each agency to conduct a study analyzing the impacts of telework policies implemented due to the COVID-19 pandemic. Specifically, the study must analyze any adverse impacts on the agency, real estate and locality costs, agency failures to provide adequate network and data access to employees, and any degree to which the expansion facilitated the dispersal of personnel around the United States. Each agency must submit a certified telework plan to Congress before expanding its telework policies. A plan must include a certification by the Office of Personnel Management that the plan will have a substantial positive effect on the agency, including by increasing the dispersal of personnel throughout the country and reversing any adverse impacts detailed in the agency's study. The certification must also provide that the plan will (1) substantially lower the agency's real property and locality pay costs; and (2) ensure that teleworking employees have adequate network capacity, communications tools, and related equipment to be fully productive without substantially increasing the agency's overall costs for these.