No, if all you want is detecting which one of 20 websites a user is browsing to, which you can by checking how much power it uses, you can definitely do that fr

No, if all you want is detecting which one of 20 websites a user is browsing to, which you can by checking how much power it uses, you can definitely do that from traffic patterns even if the traffic flows through a vpn. And this ‘leak’ assumes a user has his phone on a charger while it is already full, there is no guarantee it works.