This could potentially be interesting. What do elven trances do for elves, and what it means to live a 1000 years? Instead of We-like-trees-elves and We-like-stones-dwarves, I'd be curious to see what a "fantasy alien" species/culture could be like.
The thing I'm unclear on is, if does/could work, then why it hasn't been done by now? I'm not up-to-date on the latest fantasy novels, but I think of Asgardians from the MCU, or elves from The Witcher, and they're still just humans with cosmetic changes.
Then in RPGs specifically, are players able to roleplay an alien dragonborn, or is it still a human with a dragon head?
In my current Wild Beyond The Witchlight campaign, I like to play up the Feywild culture, pulling whatever there is in the adventure and in Domains of Delight. Honestly, it is hard and time consuming to learn and present, but the end result is that it feels like a separate plane with its own rules and its own culture that isn't found anywhere else. It doesn't feel like the Prime plane. That's the closest I've gotten to pushing the envelope on non-human experiences.
IMO . . . .
It's not a binary thing, but a slow evolution with steps forward and steps backwards. In official D&D, there has been additions to the lore to make elves (and other creatures) more differentiated from each other and from humans . . . but again, while fantasy takes influence from sci-fi, it isn't sci-fi. And WotC is hesitant to go too far in changing anything, as D&D has a long history and fans who like the way things have been. Changes, to be successful, have to be subtle, slow . . . and of course, cool. WotC seems to be stepping this up in response to recent discussions over the problems fantasy has with race. Long overdue IMO, but then again, perhaps the community is finally ready. Well, some of us.
One of the coolest and most dramatic changes to elven lore was, IMO, in 4E when elves, eladrin, and drow became a trio of cousin races with lots of new story. It was too much, too fast, on top of many other changes to the game and many gamers were not happy.
WotC also has to be careful about fleshing out various races too much, as that is traditionally the domain of the DM. Give too much detail, even if interesting . . . and then folks break into "love it" or "hate it" camps (more so than currently). Keep racial/cultural details light, and individual tables can take that framework and build on it their own way.
Comics are a wild blend of fantasy, sci-fi, and other tropes . . . and different "races" in comics often have the same problems. Science fantasy like Star Trek usually has this problem as well, Klingons and Romulans are about as different from humans as elves and dwarves are, as in not much.
And I'm not really advocating for making different fantasy and sci-fantasy races more alien . . . go to far with that, and they become unrelatable. Perhaps a bit more alien than is traditional, perhaps. For me, it's about being more mindful about understanding the difference between "people", "monsters", and "spirits". Is it okay to slaughter all the orcs? Well, are they "people" or "monsters"? In D&D, they traditionally are coded as "monstrous people" but evil, savage, violent . . . . the same language humans use in the real world to demonize other groups of humans.