About how strong is Hexy at its strongest do you guys think? Like ELO range and rankings etc.

And if anyone knows what's the difficulty spread? I recently downloaded it to practice against and noticed there were multiple difficulty levels.

It seems to me that Hexy is not very strong.
Perhaps this is an erroneous opinion, since Hexy always plays almost the same way, and you learn to play against him. I started winning against him at the strongest level after about 2 months of training.
The strength of the levels differs significantly. Beginner players can win against the first level.
What exactly did Hexy seem weak to me:

1. Hexy likes very much to move to the center, and this is most often not the strongest move.
2. Hexy really likes to just pull the bridge from the center straight to the edge, and this is often a rather weak move.
3. Hexy does not occupy acute corners (and obtuse ones does not always).
4. Hexy does not react when you occupy an acute angle.
   This is by strategy.
   As for tactics:
   5: Hexy doesn't know Tom's move !! (Oh! what a pity!)
   6: Sometimes he didn't find the tactical solutions that a mid-level player finds (I can't remember the exact examples now).

But most of the time he's good with tactics. He sees well such mechanics that seem counterintuitive to a person, and therefore are often complex to find.
In my opinion, if it could be compared with chess, I would say that he plays on the boundary of the 3rd and 2nd category.
But taking into account the fact that (as I wrote at the beginning) his weak game can only be an illusion, perhaps he can be compared with a good second-category or even on the boundary with the 1st category.
This opinion was created mainly on the basis of how long it took to start consistently winning against him.