That makes absolutely no sense.
If they've given up on Shadowlands and 9.2 being successful, there'd be no reason to drip feed bits of animation or dialogue to get people to care about the brand. People who don't care about an entire content patch aren't going to be invested in a jumping animation. There's no appreciable gain in generating hype that way.
If they'd given up on Shadowlands/9.2 and wanted to drip feed leaks to get people to care about the brand, they'd be putting in little bits of 10.0 assets into each build. A grass asset, a weapon texture, a random string referring to quest completion progress a subzone not in Zereth Mortis. Tweet out concept art for an armor piece. Not individual bits of Sylvanas' fate, a thing that is wholly Shadowlands/9.2