For newer Apple apps, sometimes the keyboard shortcuts simply don't exist. I believe part of the problem here is the deprecation of AppleScript, which means there's no incentive to spend time on consistency, and the other part has to do with organizational indifference towards all the wonderful UX innovations from the past.
What Apple has successfully accomplished, in collaboration with other 'big tech' companies is drastically reducing user expectations from their software. I wouldn't completely blame the AppStore's forced race to the bottom for this alone. There is still a huge market for tasteful apps that cost more (even sometimes with obnoxious subscriptions), but if even Apple isn't leading by example, why waste time on it if you could just build another simple note-taking app.