There isn't a single weapon in canon that does as much by itself as Rider's, save for Myrtynaster, which works because at that point it's mostly just a magic wand and not a transforming weapon. If I'm remembering correctly, the only weapon with three forms is Pyhrra's, but even her weapon is a lot simpler since its forms are just a rifle, a sword and a spear. Compare that to a greatsword-flamethrower-three mode boomerang-glider and you can see that one feels a bit more cluttered than the other.
In general, having a character with super versatility that can do so many things at once tends to lead to them feeling like a Mary Sue. There's a reason Batman's utility belt is kind of a meme.
Honestly, methinks you've got a functional weapon with just the boomerang, sword and flamethrower combination. I'd remove the whole shtick of different combinations of three settings, and also the glider function. That mostly feels like unnecessary stuff.
I'd also generally rework the Semblance, because it feels a little bland right now. It's not as personal or character-based as the ones we've seen in canon, as far as I can see.