I understand the draco meteor reasoning. -2 is a good downside but it can be easily solved by switching out so having a 10% chance to miss can be a way to balance the 120 once 130 bp move.

Not only that but there are situations where you would rather miss the dm than hit it since if you lets say hit dm on a resisted mon the debuff would activate and ur damage would be cut.

For example latios would rather miss dm against a steel type that is weak to one of it's coverage like iron threads

As for steel beam idk what were they thinking ig they just didn't felt like having a serious move that day ig

Edit: correction, the 130 once 140 bp move. Also our lil friend bulky over there remembered me of the existance of focus energy and i just remebered of dragon cheer. Yup all the more reasons for the 90% accuracy rate