That seems like trying to address one of the symptoms, not the underlying problem. "First meaningful paint" means nothing to me, depending on what the developer means by "meaningful". Why can't I just have the whole page load and display quickly?
A lot of this nonsense is because of mobiles. Mobile browsers don't handle some UI elements (checkboxes, radios, drop-downs) very well, and all the browsers have "interesting" incompatibilities; so developers use these compatibility shims, which usually result in a badly-degraded desktop experience, and slowness for everyone.
So I'm blaming the mobile browsers. They don't deal with standard markup properly.
Unless you have something specific you want to communicate and then its up to you to decide whatever you find meaningful to show first.
But now tools such as Google Lighthouse and Next.js logging first load file sizes makes it quite tangible to focus the team on and advocate for faster first meaningful content paints.