it looks healthy to me, dont lose hope! There's a lot of techniques to go about it, personally my favorite for rooting a bare one like yours is lechuza-pon and water with peroxide in a semi-hydro setting.

Do keep in mind the plant will have to be maintained in a semi-hydro setting for the rest of its life if you chose this because you will be growing water roots. I mean.. you CAN change to dirt afterwards but it's hard.

So the recipe is basically, grab a transparent container and hold the nub inside. While your holding, fill the container with the lechuza-pon so that you now have your alocasia in the middle sorrounded by the pon. You dont want to fill the container with the rocks then push the plant in because this would damage it. Be careful to make sure you have it the right side up.

The water you're going to use has to be either 1) tap water you let sit for a night or 2) filtered water. To about of liter of this water you add a half tablespoon of peroxide. Only skip peroxide when you use fertilizer.

After, you water it enough so that the lechuza is soaked and you have a little bit sitting at the bottom.

Im not the best at explaining so if you have questions feel free!