The magicrepair .cfg file is indeed the only way to repair magic items. The deluded developers had the idea that magic items were the sort of thing that should be saved for emergencies, but for an open world game like Daggerfall that has infinite quests, that doesn't work so well. This is especially true for items that are buyable, which are cheap to repurchase (from the same Mage's Guild) when they run out, or that are custom made, where you can just use something highly durable (like a Daedric Cuirass) as the base and just add Feather to it.

On the other hand, for repairing magic items, you actually don't need the cheatmode line.

Battlespire, which unlike Daggerfall has finite items and enemies (as well as finite repair opportunities), seems to match the developer's intent much better, and in Morrowind they just gave up and made it so that magic items recharge on their own. I tried this with the Oghma Infinium and, unfortunately, you can't redo the quest (unlike in Arena).

Don't know if it works this way for other artifacts, however.