Yeah, I found the pacing to be frenetic. I chalk that up to editing decisions by Nolan/Lame and the fact that Protag knows everything about everything (or after learning about it totally makes sense of it).
Like, he knows who Sator is, he knows of Soviet-era secret cities, he knows a Goya painting right when he sees one, he knows what Freeports are, and his wits are just too for anybody to be able to process and respond with as he does (claiming "bungeejumpable" a non-word, referencing Whitman, the "Mars" joke, I mean that just goes on).
Admittedly, after scanning every shot cut of this film (for reframing purposes) and after reading the screenplay, "slowing the movie down" helps with a lot of things. JDW didn't provide the most personality and perhaps intentionally so, but Protag gets much more character when slowed down. Even still, knowing everything about everything wasn't my favorite thing to watch in this movie.
This movie always bugs me with its slow-paced action, too. The firetruck is driving like 15 MPH, the plane is traveling like 20 MPH, and the gunfire battle at the end shows no purpose to reverse combatants that will provide any impact to those operating conventionally.
I like Nolan playing originally with things, but this one needed ironing out and perhaps a little more oversight. And yep, Branagh hammed it up too much as well.