Unknown to me before I first used the SSB Link amiibo, only the first time you use the amiibo will spawn Epona for you.
So I used my amiibo for the first time and got Epona. Thinking "Well, I don't need her right now. I can get her back later" I fast travelled somewhere else without registering her at a stable.
Now I know that she will never spawn again from that amiibo, so how can I get Epona back? Will she be at the place where I left here? Is she a wild horse now or did she despawn? Can I use a different SSB Link amiibo to get her back?
Edit: This question is not a duplicate of What are the requirements for unlocking Epona? The difference: I got Epona on the first use and I left her alive, but unregistered at some place I do not remember exactly. I just want to know if I can still find her there, theoretically.