The problem with Conqueror is not the true damage component. But the fact that a million items have been reworked to the point where there's infinite attack speed and every Conq user item has CDR.
Or the atrocious reworks that were intentionally designed to allow Champs to insta stack and proc Conq. Most notable examples of this idiocy would be Spear of Shojin and Pantheon.
Congratulations! You just successfully made armor meaningless.
Then of course there are abominations like Yi and Tryndamere which are a category onto themselves.
Tho it's also worth mentioning that Conqueror is a bandaid meant to fix the problem of the fact that Lethality is useless and there's barely any of it anywhere. So you can't really itemize for killing people who stack Armor.
This is especially notable considering the abundance or Magic Pen and the total uselessness of Magic Resist. All AP users are basically doing true damage at all times...while benefitting from other useful runes on top of that.