Tough one.. I’ll give the career to AD, but the peak to Embiid. I have AD ranked slightly higher, he’s around the top 60 and Embiid is in the top 75.
Both are injury prone, but as of recently, Embiid has been more so. Embiid at his peak is arguably better – he won 2 scoring titles and MVP. He’s nearly unstoppable near the rim and in the post. He’s a very solid defender and probably on par with AD in that area.
AD at his peak is probably 90% that of Embiid. He’s got more range than Embiid but not quite as dominant in the paint. He’s just as good defensively.
AD’s also had the good fortune of playing with Lebron James, and had a very good championship run in 2020, I would say he should be co-MVP with Lebron in that Finals. This pushes AD’s career and legacy up a notch compared to Embiid.