The main reason I liked evil versions of the heroes is they actually provided a challenge, most of the week monsters are poorly designed and even poorer fighters, there to make the hero look awesome more than anything else, which is fine, to a point but it was always thrilling to have an Evil Version turn up and knock them down a peg. So an Evil Version is always welcome from me, if the villains aren't putting up much of a threat which is sadly pretty often.

People have problems some of the Dark Riders because they are just evil copy and paste of the protagonist... while others are just evil with no root..... so they are villains. Every dark rider is a villain. And yeah, you can complain at me all you want for thinking Dr. Maki is a "dark rider" in spirit and not literally. Do I lose credibility for this?

Yes, having rider vs rider fights are always fun or at lest a rider who is there for their own goals like diend

No, you lose credibility because your comparison makes no sense. Maki and the Purple Greed had the same desire (The world to end), and Eiji had his own desire too (To spread happiness/prevent suffering or something along those lines).
The dark Rider of OOO was OOO, who had the desire for everything.

You're trying to treat "Dark Riders" as something more than they are, when they're not. A villain doesn't have to be a Rider to be the hero's counterpart. Eiji and Maki were counterparts, but that doesn't make the Purple Greed and Maki any more of a Rider than it does Shadowmoon.

You're making the concept of the "Dark Rider" something more than "Evil Kamen Rider," when that's all it is, which is what I'm arguing against.