Star Trek comes to mind unless you disallow scifi (as high fantasy usually would iirc, though notably “space operas” really do seem to blur the line).

LOTR could be argued as such - there was an earlier age of beings from which only remnants survived, and then we also watch live as a second epochal transition takes place, where the likes of elves disappear. I mean, either way it’s not “our reality” type of age - but then again you couldn’t ask for that from “high fantasy” by definition :-).

And it’s a very common trope in video games - e.g. Chrono Trigger that is arguably the best RPG of all time (shitty graphics, even for its time, but hands-down the best story I’ve ever seen, made btw by the creators of Final Fantasy who were given the freedom to do whatever they wanted for it). Edit: another one like that is Lufia - not a ground-breaking game but highly regarded for doing what it did so very well, at its time mind you.

And I’ve seen some others where like basically Earth is implied to have been destroyed (or at least it is unclear whether it survived a world-ending event), but the singular human remaining lives on, in space, but in something like a series of interconnected “worlds”, some having higher levels of technology than Earth ever managed to reach while others are set in earlier timeframes. And dealing with noncorporeal beings from like higher dimensions, and entities like a god inside the machine - so definitely once again mixing up heavy elements of “high fantasy” (with the likes of swords and magic) and sci-fi.

If you can dream it, someone has likely written it. Books are freaking awesome! 😎 So too are other mediums, when profits are not the exclusive focus.