I just bought an Arabian. I’m 160#, and my wife is 125...we don’t need a big horse. Leg strength has more to do with proportions than size - thoroughbreds are big horses with thin legs. Good for speed, but blinding speed isn’t all.
I had read that Arabians are pretty strong for their size (and also pretty durable, with good stamina). I'm a man-sized woman. When I was young, I weighed about your poundage, but now am heavier. I wouldn't attempt to ride an Arabian at my current size; it'd be animal abuse.