The answer: require a written proposal for changes before a patch will even be considered unless it is sufficiently small.
Also fight AI with AI: have a bot auto reject patches unless they can link to a previously approved enhancement document. Folks who commit minimal effort will f*ck right off.
Then the cognitive burden is focused on the ideas, and code authors should have at least conveyed the intent. If they actually care to invest their skin in the game then they need to collaborate and not just drop garbage on the front door.