No, I'm not. Roger could've not been WSS, it's a possibility.
I'm saying Roger was WSS as well unless there was some swordsman who could beat Roger in 1 vs 1. The latter is possibility, but logically speaking, I doubt it.
Anyway, that's how the title works.
The MC who wants to be WSS confirms many times that the title is about beating other swordsmen in fight and not losing. Likewise, Oda confirms that upon becoming WSS, Zoro will be stronger in a fight than not only Mihawk, but Shanks as well- the only other top tier swordsman in the world now.
Zoro wanna do ZKK, he's gonna cut Kaidou down. Zoro also vowed will never lose again after Baratie. What you speak of is character's ambition. It has narrative value, but never the canonical fact.
"Roger was WSS unless someone beat him in battle" is you contradicting the fact that Roger excels in haki with no one in the entire world mention him of being WSS on your own, Roger having strongest haki specifically without being WSS, while WSS Mihawk is better than Shanks specifically in sword skill, are on-panel canonical facts, unlike Zoro's ambition to never lose again etc which has been trampled by Kizaru, Kuma etc.
You stating a character's desire as facts becomes silly when you're not being responsible in giving the proof of Roger being WSS as support of your argument, exactly because there is no one saying that, everyone dismissing that canonical fact of yours and its irrelevant for them, just like how Kaidou is WSC without being the best in DF usage alone or club mastery alone or durability alone.
Stop saying canonical facts here and there while Kaidou even dismiss WSS as powerlevel representative, but proceed to hail PK as the power peak and haki peak instead of WSS while he personally knows Roger and Xebec who were both top swordsmen, and Oden who scarred him using swords, but never even remember about Roger being WSS.