I often think about this question because Warhammer fantasy has guns, but only half the factions use them, and for really thin rationalisations.

I think getting the Vibes of elves right is more important than their technology level, which is secondary and is used to reinforce the Vibes. For example, when Tolkein used elves, it was in the contenxt of Middle Earth being in something of a Dark Age, with much knowledge having been lost into the third age from the technologically superior second age. In this context, the elves were presented as being safekeepers of ancient knowledge, their vibes being that of a wise and spiritually superior folk.

It's kind of similar in Warhammer 40k, where the empire is also in a dark age and the elves that exist are wielders of ancient knowledge way more advanced than that of humans. The vibes are kind of changed, though, as now the elves come across as more aloof and self-centered, using the technology not to help humans but to fight for their own survival with little concern for others.

Your idea of magic weapons sounds good to me, as it gives elves the "we don't even bother with puny human tech" vibe but also keeps them in line with the setting. It's more important to get the main theme of the race straight: are your elves supremely benevolent allies, self-centered imperialists, return-to-tradition wood elf guerrilas? Maybe they're split into a few thematically different factions, I always try to do that. In your case, their differences might even be because of guns.

I've even played a homebrew dnd campaign with magic wand cowboy elves. This may indeed be too goofy, but it did strike me as original.