I have tried to sharpen my pizza wheel. With little luck, I might add.
Then I bought a rocker knife. I would toss the pizza wheel, but my son seems attached to it, even though we haven't used it once since I bought the rocker knife.
Years ago, (decades actually) when I worked in a pizza joint while I was in college, we use a huge knife to cut the pizza. The owner kept that thing sharp. I won't say razor sharp because I don't think the thin blade of a razor would be much good cutting hundreds of pizzas per day, but really sharp. And even 5'2" no-upper-body-strength me could easily cut the pizza up in seconds with that thing. It wasn't QUITE a rocker blade - in fact I have no idea what kind of knife it was, I've never seen the like before or since. But it made short work of the task at hand. It was big enough to go all the way across a 14" 'za - maybe even the 16" jumbo, but I'm not as sure of that. Not a toy, at any rate. I could have turned Crocodile Dundee's knife trick right back on him with that thing, LOL!