Wow. Just saw this over Yom Tov. Rav Avigdor Miller on Tefillah, just published (2021), by R' Yaakov Astor, quotes from his shiurim. [He says in the introduction that some of the quotes were lightly edited. I couldn't tell which shiur exactly it came from.] Anyhow, p. 127:
Question: In P'sukei D'zimrah there are so many selections from Tehilim, and the Rav has told us that every word is a gem and an opportunity for perfection of the mind. But can one really concentrate on so many verses and so many different thoughts?
Answer: Certainly not. And therefore, you shouldn't even try to say everything. Just to rattle off words and not gain any da'as, is worthless. It's not completely worthless, but it's just about worthless.
Instead, take your time. "Tov ma'at tachanunum b'kavanah m'harbeh b'li kavanah - Better to daven a small amount with concentration, than to daven a lot without concentration. Say a little, but think about what you're saying. Study the words and understand what you're saying. That's the real achievement in davening.
Now, of course, if you have a great deal of time, you can start davening three hours before the tzibbur, and you'll be able to do justice to a good part of the P'sukei D'zimrah. But whatever it is, you should spend time using your head in davening, not just your lips.
"You shouldn't even try to say everything."
Too bad they didn't ask him about other parts of tefillah, though.
Counterpoint: A very choshuv yunger man mentioned to me what Rav Shach z"l wrote in his haskamah to R' Meyer Birnbaum's Darchei Hatefillah: Use this for studying about prayer, but don't use it while you pray. You aren't supposed to be studying prayer while you pray, you're supposed to be talking to Hashem.
That would seem to go against at least the "three hours" part of what Rav Miller said, and perhaps the whole idea of "gems" and "so many different thoughts". The words of P'sukei D'zimrah are indeed gems, but that doesn't mean you should spend time examining all the facets while you pray.
I don't think that would contradict a middle ground, where someone might skip part of the davening in order to do a decent job with the rest.