On a (slightly) more serious note - what this article shows is that when it comes to long-running shared-universe stuff the answer to the question "who created what?" is almost always "it's complicated"
For The Comics Journal @comicsjournal.bsky.social, I wrote an in-depth investigation into Roy Thomas, Len Wein, and the curious case of who created Wolverine. Featuring interviews with many of the key players.
Like, who made Deadshot? He's not Wolverine-famous, but he's been in a movie, cartoons, videogames...
So who made him? According to Wikipedia it's David Vern Reed and Lew Sayre Schwartz (Bob Kane is also credited because he was good at it). I don't recall a lot of argument about the matter.
BUT...
He doesn't look like the character as we know it today, has a different motivation (to 'replace' Batman), doesn't have the same weapons (regular guns instead of the gauntlet-things), nor the fatalistic approach.
Other than the name and using bullets to kill people he's unrecognised.
Thirty years later the character was almost completely re-invented by Steve Englehart and Marshall Rogers - now a lot closer to to the one we know (especially in design terms)
This was 1979 - before internet, before collected editions... Deadshot was in one issue decades ago. The number of people who remembered him then would probably be in low triple digits - the number who cared even lower.
Nothing would've stop Englehart and Rogers from just creating a new character for the story, there's value in the backstory but they could've say "oh, Batman put him back years ago and he's angry." I assume most readers would accept it.
But they didn't, they wanted an actual connection to the past.
Deadshot is almost a Ship of Theseus situation. Like you said, all Englehart kept was the name when he brought him back and the outfit Rogers and Austin created is nothing like his original appearance and a vast improvement.
