Fury doesn't scale with Illusion perks at all—it's purely the confusion effect that matters. The spell itself does zero damage; enemies just beat each other up while affected. So if you're thinking Illusion perks will make Fury hit harder, yeah, you're kind of wasting points there.
That said, Fury is still genuinely good control. The confusion effect is what makes it work, and that DOES scale with stuff like the perk that boosts spell effectiveness against higher-level enemies (forget the exact name, but it's in the Illusion tree). Hypnotic Gaze is solid if you're going for the sneaky angle—casting it from stealth gets better results. Occultist is less useful for Fury specifically since you're not really trying to hit the same target twice.
If you want Illusion to actually do damage, honestly, you're probably fighting the game's design a bit. It's a control school. But if you're hybrid melee anyway, lean into that instead—pump your one-handed damage and use Fury as a setup tool to make groups tear each other apart while you clean up the stragglers. That's where the real damage comes from.
What perks do you have allocated so far? Might be easier to say where to pivot.