I need to go back to this for my own sanity before stuff becomes false information:
1. McGregor's Killmonger's first panel had him break a tree in half with his highly fashionable spike belt. T'challa then swung on a branch with full force and kicked him and Killmonger didn't move. In their second fight in Panther's Rage, T'challa compared fighting Killmonger to fighting his dad as a child ie he is vastly stronger than T'challa. Killmonger is shown to 100% not only T'challa's equal but actually surpassing him in physical abilities. What we don't really know about Killmonger's McGregor is how he ended up enhanced (it is vague). But all panel evidence points to Killmonger being a variation of comic book peak human ala the same class as T'challa and Cap. Also note, Killmonger never "outskilled" T'challa, which is a popular way non-enhanced people beat enhanced. He was just explicitly shown to out power T'challa.
2. T'challa suit isn't always in the weave. Especially under Hudlin. But also, the fight with Priest at Warriors Fall's had T'challa's habit shredded and torn to bits. Even T'challa's fight with Iron Fist, his suit didn't get that damaged. While not said, it is highly likely T'challa ditched the weave for his tribal fight with Killmonger. When he took the killing blow, he was completely shirtless. Also, despite Rise retconning when the weave first appeared, there is obviously no way McGregor could know that. We just have to assume he changed clothes for Panther's Rage if you want to use headcanon.
3. Zuri said Killmonger had genetically enhanced strength + whatever the death regiment did to him upon Resurrection. That, once again, points to the fact he was enhanced BEFORE the resurrection altar... the Resurrection altar just changed him more