Am I suffering some kind of confirmation bias, or does Spock spend an unusually large amount of time expressing emotions, for someone who's supposed to never express emotions?

100%

So much so that I’m at the point where I’m still wondering if this show is still canon.

I really like Strange New Worlds. The episodic nature with overarching storylines is the right direction for Star Trek, but really wish they had used this cast to make a show with a new crew in a new ship set post-DS9.

I disagree. I really enjoy this show and I can give the writers some creative license as a prequel for a show that's almost sixty years old.

Spock has to have a moment of crisis that brings him to the state of character he's in in TOS. I think there's plenty of room to breathe over the course of the show to allow that. I haven't watched The Cage in several years, so I don't exactly recall, however from what I do recall, Spock shows a lot more emotion in the pilot vs. the beginning of the series with Kirk.