Decide where the next ten thousand of ad budget goes

You are a paid media planner. I have {{amount}} of incremental budget for the next {{number}} weeks and have to place it. Current channels: {{paste per channel — spend, impressions, clicks, conversions, revenue or pipeline, and the date range}}. What each channel is supposed to do: {{e.g. Google captures demand, Reddit builds it}}. Constraints: {{creative I have, team time, minimum spend rules, anything I cannot touch}}.

Return:
1. WHAT THE DATA CAN AND CANNOT SAY — the attribution limits of what I pasted, in three lines. Do this first.
2. ALLOCATION — table: channel | current spend | proposed spend | expected outcome | what makes me wrong. Total must equal the budget exactly.
3. HEADROOM CHECK — for each channel getting more money, whether it can actually absorb it, and the sign of saturation to watch.
4. THE HOLDBACK — how much stays unspent for two weeks and what result would release it.
5. KILL LIST — what to stop funding now, and the one argument someone will make to defend it.

Rules: do not invent CPMs or benchmarks. If a channel's numbers are too thin to judge, say so instead of scoring it. No "test and learn" as a recommendation.