I think most people accept the Desaad retcon (though that is the most powerful I've ever seen Desaad), or are unaware. Zvelf does have a point in that it isn't specific about which confrontations were or were not DS or Desaad, but we can certainly speculate that it was his worse showings prior to that reveal....we do clearly see an instance vs. Superman, and another with Hawk and Dove, Dr. Fate, and some others...but 586 wasn't his only run in with Superman prior to this retcon. With the Thanos retcons, we have an explicit callout for a low powered version in Kazar, a high powered version in Thor, and the Squirrel Girl issue was explicitly a clone.
That said, I think there are clearly some instances where it wasn't Desaad...for example, I think we had a good indication that pre DOS Doomsday was at least a reasonable and substantial threat....seemed
the whole point of the story.
Was Orion fighting Desaad who then faked Darkseids death? I don't think so. And yes, Orion seemed every bit as capable as DS in that fight, and DS knew he had to fight hard or Orion would catch on.
There is other circumstantial evidence that further reinforces that characters like Martian Manhunter, Orion, Superman, and other DC top tiers can feasibly beat Darkseid head to head, and not necessarily be depicted as underdogs in doing so.
Thanos, in early continuity may well go in the same ballpark. While people will talk about Mar-vell only beating Thanos because he surprised him, he was effective against him. While it is kind of a lower showing for even classic Thanos, I could certainly see Thor, Superman, Orion and the like being written to beat him.....BUT.....
once Thanos was powered up by death, he's been VERY consistently portrayed or protected via. retcon. I don't like the heavy handed retconning, and I don't like that Darkseid is VERY beatable by Orion, Superman, etc. but at this point, I think its pretty well established.
Thanos' level of protectionism is WAY above that of DS.
Now, if you want to argue that DC top tiers will consistently be huge favorites against Marvel top tiers, its another argument, and if you think Superman is an overwhelming favorite in a fight against the likes of Thor, Silver Surfer, etc. then saying Darkseid would do so is at least internally consistent with your viewpoint.
However, if there is anything like competitiveness between Thor, Surfer, etc. and Orion, Captain Marvel (DC), Superman, Martian Manhunter and the like, then Thanos is substantially above Darkseid as well, or MAYBE you could make a reasonable argument that Thanos>Darkseid>top tiers, or even be a little more granular.
Likewise, if you draw the equivalence between Darkseid and Thanos, as opposed to between the top tier heroes that have more points of comparison and more showings, then yes, Orion has a very good shot at beating Thanos head to head, and potentially just flat out overpowering him....because yes, that is what you're saying, because if Darkseid is a 100 in power, guys like Superman and Orion are no lower than a 90. If Thanos, as he's been portrayed since powered up since death, is a 100, Thor and Surfer are certainly no better than a 70, and may well be substantially lower.
I would say that if you put Thor as a 100, Superman, Surfer, Orion, etc. are all within about 10 pts of each other, whichever way you think it swings....and Darkseid is in the same ballpark. But Thanos is up in the 150 range.
Again, if you assigne DS and Thanos equality, IMO you're saying Darkseid=150, Superman and Orion are at the lowest 135, and Thor and Surfer are around 100, and I don't believe the crossovers support that level of disparity at all.