Not really.
She was tricked by Saurfang to desmask herself in an outbreak again. She lost herself and thus was forced to leave. Else the Alliance and Horde woudl have just kiled her since the Orgrimmar Horde wouldn’t stand at her side anymore.
Saurfang knew he had no chance of winning, what does a mak gora do if you know you’t lose aand this change nothing in terms of the war to happen? He gambled with Sylvanas inability to controll herself and won. That was the only point why he even challenged her.
Since the Night Warrior (Who is saving them basically as she is rampaging through Thorgast to even get there) wouldn’t be in Shadowlands without her having to speed up her plans (or even finding a new one sind we don’t know if the destruction of the helm was the plan all along or if it was just plan b now since everything else failed) .
So without Sylvanas being forced to leave the Horde would have to deal with the Night Warrior now since she woulnd’t be in Shadowlands.
And thus there would be an even bigger war with even more deaths as we know that canonly the Night Warrior is capable of killing old gods and a demon invasion. So not an easy thing to deal with.
Long story short, teh souls would not have been saved and even more would have been sent there.
This is actually true, but only half of the world woudl want to kill her, now all of it want to.