To this day, I don't think anyone with any knowledge of the situation agrees that bumping Truman's original story into the then-current timeline was a good idea.
That seemingly small tweak was the domino that sent the whole thing tumbling down. Without it, Ostrander wouldn't have spent so much time trying to reconcile everything, and could've just told good stories moving forward. I firmly believe the Hawkworld monthly would have lasted longer, as would have the follow-up title. There would have been no need to scorch the earth and leave Katar in limbo for all those years.
It's not Hawkworld's fault. Everything would have been fine if they just added a simple '10 years ago' or '15 years ago' caption. It's the decision to say Hawkworld took place in the then present day DCU that sent the whole thing spiraling downwards.
That only came into play as a result of the 2018 series.
Prior to that, you had almost eighty years worth of various Hawkman stories.
There were clearly defined differences between "Golden Age" Hawkman and "Silver Age/Bronze Age" Hawkman, which were two separate characters each on separate Earths. And after CoIE, even though there was just one Earth, they were still two separate characters. And there were still new stories involving the (previously Silver Age/Bronze Age) version of Katar Hol.
But a few years after CoIE, there was Tim Truman's Hawkworld series, a sort of reimagining of Katar Hol. And once DC decided that the Hawkworld three-issue series would take place in the (then) "present day", they had to figure out how to explain why there were stories involving Katar Hol on Earth before he now had come to Earth.
It's really hard to explain how much of a screw-up it was by DC if you only recently started following Hawkman. And every time DC tried to explain away an inconsistency in Katar Hol's back story, it seemed to create one or two new problems, so it's hard to say that with the reincarnation through time and space theory that EVERYTHING that ever happened now really happened. Because that means all the original stories AS WELL AS THE RETCONS CHANGING THOSE STORIES ALL are part of continuity.
Well, regardless of how many Hawkmen there have been, I rather like the Silver Age version. But that's because the first time I really paid all that much attention to the Hawks was when Showcase Presents Hawkman vol. 1 came out. One thing I really liked in the Silver Age Hawkman was all the little invented Thanagarian socio-cultural bits in that comic. One of them was that since Thanagar was supposedly without want, all of the criminals on Thanagar just did it for kicks. There was also a detail about how married women on Thanagar wear earrings rather than rings on their fingers. Plus, just the whole "winged policemen" thing. It was a nice touch when most Silver Age DC comics about alien planets were more focused on what scientific advancements they had made.