You can see in the 100T v NRG vod at 3:02:33 that Asuna is using a Deathadder V2, a mouse that came out in 2020. Not only that, but he's using the wired variant, not the Pro version.
Not even close to the weirdest setup choices from pro players:
Mezzi from vitality's cs team uses quake key layout
Jackz (ex G2 cs) plays on arrows
Amanek (ex g2) has inverse audio (he hears sounds which come from the right side in game in his left ear)
And MATYS from fnatic uses a 10 year old mouse pad https://www.hltv.org/forums/threads/2906711/matys-mousepad