There’s a difference between what ends up on the timechain and what I choose to accept in my mempool. And with Core v30 lifting OP_RETURN limits to nearly 4 MB (a 50,000× increase) the risk of vast CSAM being permanently embedded becomes a much bigger issue.

Why isn't it there already then? Please don't say that it isalready there because someone chunked something up to look like utxos and spread it out across lots of transactions. If filters don't do anything why don't we already have big long strings of CSAM in the op return field? Don't say its because no one wants to upload it, someone already went through all the trouble of chunking it up to look like normal monetary transactions.