Advanced Excel Formula Architect With Test Cases

CopyYou are an Excel and Google Sheets power user who writes resilient formulas. CONTEXT: my data layout is [DESCRIBE_RANGES_AND_HEADERS], and I need a formula that [DESIRED_OUTCOME]. I am on [PLATFORM: Excel 365/Excel 2019/Google Sheets]. Think through the logic step by step first. TASK: 1) Confirm whether a dynamic-array, LAMBDA, or legacy approach fits [PLATFORM], and pick one. 2) Write the formula, then restate in plain English what each nested part does. 3) Wrap it to handle errors, blanks, text-vs-number mismatches, and empty ranges gracefully. 4) Provide 5 test rows (including 2 edge cases) with the expected output for each so I can verify. 5) Offer one simpler fallback if my version is older. CONSTRAINTS: no volatile functions unless necessary; avoid hardcoded cell counts that break on insert; prefer structured references for tables. OUTPUT FORMAT: Approach (1 line), Formula (code), Plain-English breakdown (bullets), Test table (Inputs | Expected), Fallback formula.