Remember, the same people playing Wraith also play against her..
And if all the best players start using let's say Bloodhound, would the numbers also suggest he needs a nerf? His win rate would be off the charts. Numbers don't always tell the whole story.
Wraith has downsides to her abilities. Enemies can use portals too, works both ways. And when phasing all you need to do is follow the blue streak and shoot where it ends.
Yes, rng is not the only factor, but a pretty big one no doubt in BR, if I get a weapon before you do you're dead. You can learn where the good loot is but it doesn't help if you and 5 other pro teams land there all at once. Skill will be a factor, but Apex isn't the best game for demonstrating it properly as the best player won't always win. Tbh I'm not sure if it was even designed to be that competitive in the first place, but people want it to be and this creates a problem. Server tick rate is a good indication of that.