It is common to see resumes get picked apart but simply getting the timing right can make a massive impact. Examples- Zhang would be a good win after his wins over Joyce but before that would have been considered a 40 year old cherry pick. Joyce would have been a good win before the Zhang fights but would now be seen as beating a hype job/ damaged goods. AJ would have been an excellent resume boosting win before Ruiz stopped him. Whyte would have been a good win before Povetkin brutally KO'D him. Now he is seen as a gatekeeper rather than top contender. Ruiz would have been seen as a very good win after he beat AJ, now he is seen as an inactive, past prime fighter. These are just a few examples at heavyweight. It is all about striking whilst the iron's hot but the best fights generally don't get made when they should.
Typically fighters had many more fights against quality opposite to gauge consistently, flukes, and the likes.
Fury would have been seen as a cherry pick if Wilder done what he was meant to the first fight and KO Fury
Pretty much this the problem is most of the top 10 Heavyweights have very little in regards to wins vs ranked opposition, if they were fighting more often against top opposition then maybe all of them would have a few more losses on their record. Joshua probably has the most filler on his record out of all the other top Heavyweights but he still hasn't fought Wilder, Fury, Zhang, Joyce, etc. Usyk only has the wins over Joshua atm. Fury since beating Wladimir only has notable victories vs Whyte, Wilder, he still hasn't fought the likes of Joshua, Usyk, Zhang, Joyce, Hrgovic, Ruiz, etc. Wilder only has 2 notable wins against ranked opposition. Zhang only has 1 notable win atm vs Joyce. That's the point i'm trying to make it's hard to gauge because the top Heavyweight's aren't fighting eachother.
But this is the problem, the notion that the iron has to be hot in boxing. A fight should be able to lose and not be seen as damaged goods. When the best fight each other they will lose, it happens. Justin Gaethje has lost 4 times over the last 6 years and every time it's been a meaningful victory over him every time. If he's beaten again it will be a top defence by the champ. Boxing has too much emphasis on zeros.
They leave fights to "marinate" for too long and by the time they happen, they are a lot less valuable. Pacquiao Vs Mayweather in 2009/ 2010 would have been a legendary win on the resume for the winner, the iron was hot. Instead, they had a retirement fight. I would love if boxing was more like UFC with just 1 belt and champion has to defend against top contenders and contenders have to earn their shot.