Well stay is being blocked by both g4u and levitating's radio. And yes it's real popularity is not being shown either. But once radio kicks in more stay will overcome both.
It's obvious billboard weights sales way too much. This is not the first or the last time stans have used sales to manipulate charts. Keeps on happening. First thing they should do is make it one copy per person for website sales.
Honestly I still find fans buying music much more organic than streaming playlisting and radio pay for play. Weighing down sales basically discourages active consumption as a whole.