We don't know what's basic, the only 2 to ever share a same attack (apart from susanoo which is just a rare occurrence) is Amaterasu, and tobirama hinted at kagutsuchi (which might not have even meant black flames, someone's flame control could have been a weaker version that just used normal flames, we don't know.)
My point is, we don't know specifically if tobirama can deal with itachi (especially genjutsu)
But it seems to me from what we do know, he can't.
Kagutuschi is just the controlling of amaterasu, Izuna most likely had it.
And Tsukuyomi is a basic MS attack.
I think the more correct way to phrase what you are saying is, "We don't have the feats to say 100% that Tobirama can deal with Itachi".
However, i would like to to remind you... Tobirama can raise his chakra and destroy walls.. Itachi already acknowledged this concept of breaking genjutsu, when Naruto was trying it, but NAruto was too weak.
Are you referring to toka senju? Lol
Mans surpassing the uchihas genjutsu collectively is one thing, surpassing their ultimate genjutsu user is another.
But like I said, he doesn't have hype or fears to help him against genjutsu, especially itachis genjutsu.
@Bold, the hype part is where you are wrong. THere hasn't been a shinobi in the leaf that has even been on Tobirama's level, till NAruto and sasuke . And that isn't enough hype?
The mere fact he already has more knowledge on the sharingan than Itachi has shown, isn't enough hype?
The mere fact the breaks stuff just by raising chakra sin't enough hype?
How does Itachi even counter his speed?