I will only stay in this one area where this specific type of enemy spawns to get the most out of this resistance. I don’t want to see the rest of the game.
And you find the plate mail with 80% fire resistance not at the end of the water dungeon, but at the end of the fire dungeon. You will never see another fire elemental after you exit here. Fire damage will be completely irrelevant, even in the final boss fight where Satan himself shows up and only uses dark attacks.
If you’re the only one using it, you could just publish the source and let us review it. Worst case we find some terrible flaw and you have to stop using it for a bit while you fix it.
But I can’t imagine any big vulnerabilities in a local frontend anyway? I’d be more worried about accidentally sending/resending requests and generating unnecessary load for the server. For authentication it’s hard to mess up as long as you’re not sending passwords to servers other than the one you’re trying to log in.