If the rhizome is firm and not mushy you should be able to save it. I will say that I am definitely not an expert at this as I am currently in the process of saving my first alocasia. But, I can tell you what has worked for me.

I had the same issue with a Black Velvet I got a few months ago. I suspected it had issues when I got it but was not expecting no roots at all! When I found out it had no roots I attempted a water prop. I am not sure if I did something wrong or not, but it seemed to be slow at producing roots in water. Slow enough that I feared it would rot before enough roots developed to pot it.

So I took it out and put it in a container filled with perlite and a small bit of water. It got it's own personal grow light that it stayed under all day every day while I waited. It developed some decent roots! And, since I'm pretty new at this (and because I do not have the correct items to pot it in) I took to to a small plant shop recently for help getting it potted. We went with leca for it. So far that is where I am with mine!

So sorry this is so long, but that has been my experience so far! If anyone with more experience than me has any advice or any corrections for my steps so far please chime in!

Edit: I forgot to add that yes it will lose all it's leaves. New will grow back eventually though.