Filter everything. Accept nothing but blocks. Problem solved.
But filters are why nodes with less than 12 GB ram take forever to sync now…did you know that? Because people can’t pay more to easily stuff shitcoins inside provably unspendable outputs via op_return, they work harder to abuse the segwit discount by cleverly stuffing data in the witness. And these outputs are not provably unspendable and thus have to stay in Utxo set…which used to be 4 GB not all that long ago.
problem not solved, relaying transactions is a valuable activity for nodes. nodes validating each others transactions is a check on miners to discourage them from filling blocks with transactions nodes dont propagate 😅 because ideally blocks with transactions that nodes care about would propagate better than a block filled with transactions nodes never seen before.
the filters werent updated to handle the bulk of transactions that bloated the utxo set (pr 28408); i would blame the LACK of filters on what caused the utxo set to bloat rapidly as these new forms of datacarriers are allowed to propagate freely on the network circumventing longstanding policy.
this is why it's important to revisit the topic instead of making the situation worse by allowing new/updating nodes relay larger OP_Return that dont propagate on the wider network prior to being mined/confirmed
