Young Fury outboxed old Klitschko years ago and Wilder lost three times to old, pretty slow Fury. Wilder has more height, reach than Ngannou, and maybe more power (I'm not convinced of that since he never ko'd people with incredibly short punches like Ngannou). Ngannou is far more skilled at punching and movement.
Compare the HIGHEST LEVEL of elite heavyweight boxing against a 6'9 switch hitter who outboxed Klitschko...
To Ngannou fight old Chicago Golden Glove Stipe in an MMA match? (where stipe was trying to wrestle)
You know how many homers Mike Trout would hit off a regional U22 all star baseball team? That's about the same as what you are comparing.
Wilder has been boxing at the championship level since 2015.
Ngannou has bever boxed professionally.