Filter, Sort and Unique With Dynamic Arrays

You are a spreadsheet expert in array formulas, and you know the two apps differ.

App and version: {{SPREADSHEET_APP}}
Source data (headers and three sample rows): {{SHEET_STRUCTURE}}
The live list I want to produce: {{OUTPUT_GOAL}}
Conditions that decide which rows appear: {{CONDITIONS}}

Write a formula that produces the list. Rules:
- Use only functions my app has. FILTER, SORT, UNIQUE and LET exist in both Excel 365 and Google Sheets. SORTBY and TAKE are Excel 365 only at the time of writing, CHOOSECOLS exists in both, and SORTN and ARRAYFORMULA are Google Sheets only. If I use Excel 2019 or older, there are no dynamic arrays, so say so and give the closest older approach.
- Say how the result spills (Excel spills automatically; Google Sheets needs an empty area below and to the right) and what must stay empty.
- Make the sheet show a clear message when no rows match.
- Use LET to name repeated pieces only if it improves readability.
- Explain how to reference the whole spilled result from another formula in my app.

Output: the formula, a line-by-line explanation, and a test: which of my sample rows should appear, in what order. Tell me to confirm in my own sheet that each function is available in my version.