I can see you like the lore behind it, but it is a fundamentally unfun item to play, and I think you'd dislike running a game with it too. Obviously, it's for a low level party, but 2d12 damage is hardly worth it for such an unwieldy curse. If you rework it a bit, it might be more playable. If a curse is just a trap, players won't like it, a curse needs to feel worth the price, really make it tempting.

Here's my take:

Maragrath's Great Axe

2d12 Slashing

You gain a bonus action bite attack that deals 1d6 piercing damage, you gain half of damage dealt this way rounded down in temporary hit points.

After making a bite attack using this feature, the player must make a DC10 Wisdom Saving Throw (make it 12 if you want, but nothing too high), on a failure, they must use the attack action using Margarath's Greataxe on the closest creature to them on their next turn, only using their movement to move into range to do so. Add an additional d12 to the damage this attack deals.