Is there an easy way to turn off web push entirely so I don't get spammed with spamification requests?
Short answer: yes. In Safari 16.1, select Preferences > Websites and uncheck “Allow websites to ask for permission to send notifications”.
Details about WebKit’s Web Push implementation and how privacy is handled [1]:
Also, in Safari you will not get spammed by requests for permission to send notifications. A website or web app can only ask for permission _after_ you've indicated interest with a gesture — like clicking on a "subscribe" bell icon, or a button that says "notify me". They are not allowed to ask you until you've taken the first step.