Rather than subsidize "white" miners in this convoluted way, why not have users donate to ALL miners by stuffing data into op returns at a fee rate high enough and with a mempool backlog large enough to deter non op return data utxo bloat (aka spam).

if spammers bid more aggressively, greater good minded users can use cpfp or other mechanisms to increase their own bid.

I doubt many users would want to use wallets that forced to donate to an anti spam fund like this.

But they might equally not want to donate to the anti spam fund the other way. And at least this way doesn't introduce a state attack vector.