As a duckie.cos fan, I always try to see if they both do the same dance trend on Tiktok (especially if its something that involves shaking ass or hips) and the difference between them is getting more and more clear.
Celebi leans more onto safe "tiktok" dances like just typical movements that just seem like the average e-girl cosplayer you see on TT (hence you guys saying its more like her just flailing around), but that probably correlates to the cosplays she wears which aren't really for dancing per se.
Compare that to Duckie/Lexi which she is mostly consistent towards her dancing being more smooth and sharo with her movements, and if there's some ass shaking, she ain't gonna be shy that's for sure, and she mostly wears outfits that reveal her body a lot more.
Overall, probably just a change in pace between them (Celebi does have better sets compared to Lexi lol) but there was a time when both of them liked to dance better than 99% of cosplays on TT and that in turn gave them that "higher" status I suppose.