RNG is meant to create excitement. You attack and might not always do the same amount of damage. You heal, it may not be a lot, or it may be a ton. You shove, you may get your enemy off you and your companions. You might not.

The problem isn't the RNG. It's the extremes in BG3, and that's the point. Shove shouldn't be so extreme. 5 ft is all you should be able to be pushed... Or knocked prone. It should very rarely send you off a cliff or into lava.

It is the extremes that make the RNG so bad. It's not the RNG itself.