DISCLAIMER: I love Critical Role and have nothing but respect and admiration for the producers and performers. Any analysis or opinions here are stated with love, and understanding that a show which is largely improvised cannot and should not be held to the same expectations as a show which is rehearsed and written with certain representations in mind.
Though I'm loathe to admit it, the fact is that transgender and nonbinary people aren't always magical. They aren't all shackled with a long involved backstory about shape shifting, royal disguises, or being blessed by fairies at birth. Sometimes, like Matthew Mercer's new NPC in Critical Role's second series, they're just your run of the mill Crown Guardsman. Source: First appearance and Named introduction.
Watch Master Bryce, a nonbinary half-elven guard, turned up during a gnoll raid on a small village and rewarded our ramshackle party for helping them fend off the attack. Their pronouns were established firmly but nothing whatsoever highlighted them as out of the ordinary. And even if Bryce turns out to be more than they appear, the commonplace introduction of a nonbinary character in a fantasy setting is still significant.
The previous campaign featured a nonbinary NPC as well, who benefitted from a long and grand introduction as the splendidly androgynous leader of a city, who then transformed into their impressive true form, a metallic dragon. Like humans, dragons in Mercer's world run the spectrum of gender identity. This character, while fantastic, was more along the lines of how genderqueer people are used to being represented: as supernatural, androgynous alien beings whose gender may or may not be associated with shapeshifting. Rarely are they depicted as simply being normal.
Bryce may become a friend of the party or merely a passing association, but regardless of that, their presence has already broken a glass ceiling for non binary representation. Sometimes trans or non binary people are great heroes, fantastic beasts, otherworldly creatures of magic—and sometimes they're just a town guard you happen to meet—an ordinary person doing their job, whose pronouns just are what they are. There doesn't have to be a reason for it, or an ordeal surrounding it. It's these lovingly mundane depictions that make people feel real and recognized, and might make cis folk realize that a switch up in pronouns is no big deal when there are bigger, hairier monsters to fight.