Let's say Zoro can see and damage rukia.
Both at full power & strongest form.
Empty space with oxygen and invisible floor that is 100000 km wide
He never said Zoro is capable of moving FTL, he just said he has dodged light beams.
Zoro's speed feats outclass Rukia's.
Wether you agree or disagree that evading Kizaru's light beam from a pacifista makes a character FTL or not, it is certainly above supersonic & in the hypersonic region.
Zoro also dodged Kuma's pressure cannon's which he claimed are light speed & again if you agree or not is up to you but that feat is certainly in the hypersonic region & I have not seen Rukia show feats on the same level.
I think people still misunderstand how haki works. It gives the user limited pre cog, so while the user themselves isn't FTL or anywhere close, they can react to lightspeed attacks by predicting the attack.
OP is all about haki, if you want to win a fight you have to be able to use your haki better than your opponent. If you can't use haki, you're pretty screwed.