HTTP/2 Server Push is becoming deprecated in Chromium. It was a novel idea but really nobody found a use for it.
Not to toot my own horn, but I've noted its limited applicability back in 2018 when everyone was saying that "you don't need WebSockets use h2 push instead." Well, guess what, one does not replace the other. Indeed, the way h2 push was architected would never have allowed it to replace bidirectional streams entirely; the browser only uses it to prime the cache, so to speak.
So, in a way, this is not a big loss. For those who still want to optimize their resource delivery, you can probably just inline them instead.