Steve Angeli has an adequate arm, that he can make all of the short and medium range throws with ease. He also did this with good accuracy, and threw a very catchable ball.
I'd put his arm on par with Jack Coan's, in terms of strength. He can make a reasonably good long throw down the field.
He also showed reasonably good mobility.
My only knock on him was his ability to sense what was going on in the pocket, that he sometimes holds onto the ball too long, instead of chucking it away.
I think that he would have gotten significantly better when it came to tossing it away or even scrambling for a few yards, with more playing time.