I note that a few Angels look scary, probably truer that the kindly human looking ones, else why would nearly every case, the first thing an angel says is some variant of 'Don't be afraid'?
One doesn't need to say that to someone who isn't afraid!
It must be especially challenging for a Biblically aware artist to depict an Angel accurately. Mostly they default to a kindly looking, wise, handsome, perfect humans with doves' wings. Perhaps a battle scared victor from the battle to throw Lucifer and his minions from the Heavenly realm would be more accurate (although scary!).
I agree that painting angels is a daunting task. God has described seraphim vividly, but not the ordinary enlisted ranks. Eventually, though, we'll know how they look from personal experience, because we'll all live among them: believers with the good 'uns, and nonbelievers with the others.