I wonder why all the manga out there don't cater isekai x monster girl waifu (except for that infamous monster tamer story).
Maybe because "Elf" for the Japanese man is just a human with pointed ears?
Even the beastmen don't look like furries at all (although they should, reminds me of that gorilla bride manga..).
If they want to sell interracial stories, they can just pair Japanese with European people (maybe some devoted cosplayers so you get the pointed ears on top), or at least make the elf design more demi-human (i.e. with different proportions so they look more like aliens than humans) so you can actually distinguish them aside from their ears.
Something similar to the fairy queen in Berserks Lost children arc could already do the trick, it looks human but at the same time inhuman enough to pass as a non-human being.
After all, it doesn't always have to be beatiful female characters. An initially ugly female (because she looks like a monster/beast) that comes with a nice attitude and character could be worth more than any oversexualized elf that is only thinking with her crotch(not talking about this manga, but the several other isekai stories that made hentai slaves out of elves).