Design Sensitivity Tables and Scenario Cases for an EBITDA Forecast

I am building the sensitivity and scenario analysis layer for a monthly operating forecast model. The key output I want to evaluate is EBITDA. The key value drivers are revenue growth, gross margin, headcount costs, marketing spend, and other operating expenses. Recommend: The most useful one-way or two-way sensitivity tables to build, including which inputs to test, appropriate ranges, and reasonable increments. The most useful scenario cases to include, such as downside, base, and upside, with assumptions that should move together in each case. Whether each analysis is better suited to an Excel data table, scenario selector, or dedicated assumptions case structure. Please explain why each sensitivity or scenario is useful for evaluating forecast risk and performance in this monthly operating model.