Elves may be fictional creatures but the setting forgotten Realms describes pretty well how elves should look like. Disregard a whole setting because "Oh hey its fictional everything goes" actually don't give the setting proper respect. Because a wold is fictional that doesn't mean that it haves not his rules if i create a world where elves are described to have spikes in the foreheads then all the elves born in that setting should have spike on the foreheads.
You don't like the setting then go homebrew. But Baldur's gate 3 is in the forgotten realms so the setting is applied here.
I thought Tolkien was the defacto go to for elves.