We also visualize her emerging from the lake as though she lives at the bottom of it, with the sword fully formed. If she's smithing the sword she needs fire, so does she live next to the lake, or does myth magic allow her to do metalwork underwater?

Once we start applying reality there are a lot of questions. Does she have a full smithing career and trade, or does she only ever make the sword? Because that means that either Excalibur isn't as unique as we were led to believe, or her entire existence is about that one sword handoff, which is somehow more objectifying than thinking of her as some kind of water nymph, slender and graceful or not, who makes or acquires the sword magically, and spends most her time doing mysterious but unrelated magic.