The vast majority of D&D races are some variation on human. Skinny humans with pointy ears, short humans with beards, etc. A difference that makes no difference is no difference.
And? They're still different. The differences don't have to be dramatic and obvious to still be interesting. Dragonborn are pretty much just humans with elemental halitosis, egg-laying, higher-protein dietary needs, and overall shorter time from infancy to adulthood.
And if you make your dominant race something other than near human, you can give up on using "medieval" or any other human style as your reference. Why would an aarakocra civilisation build castles when everyone can fly?
And if the difference isn't such a ridiculous extreme, but is still different? Theoretically all eladrin can short-distance teleport. Not often enough for it to alter how they design buildings, but often enough that it should have societal effects....but won't suddenly make their civilization incomprehensible to humanity.
I genuinely don't get this obsession with "if they aren't human it has to be TOTALLY INCOMPREHENSIBLE XENOFICTION or it's just not worth it." It's a false dichotomy through and through. Human-like but NOT human beings give us the chance to see the familiar in the strange. Just as fantastical humans being humans (and thus diverging from expectations) gives us a chance to see the strange in the familiar. It doesn't have to be differences as society-redefining as "everyone can fly" or "everyone is telepathic" or the like. Exploring the consequences of
subtle differences is a huge part of what makes science fiction and fantasy interesting--and the authors who build entire well-thought-out, rigorous worlds with only small changes have well-earned their praise.
And that's not even touching on the possibility of (for example) fundamentally different number systems or the like. Dragonborn might count in octal or duodecimal, since they have only four digits per hand. Elves might associate having lights inside the home with opulent extravagance, since a small dwelling isn't big enough to have longer than 60' lines of sight. Tieflings, being resistant to fire, might eschew safety equipment or standards that other races rely on, causing friction in workplaces. Etc. Just because the gross, general approaches to life and living are pretty much the same doesn't mean there's
nothing to see, nor that it's impossible to still have large differences that arise from small effects. Even something as small as the (4e) Dragonborn ability to heal more quickly from injuries could have altered human history dramatically.