

As far as WhatsApp goes you can download the apk directly from them if you don’t want to install the google play sandbox for some reason.
As far as battery life a big drain is google play stuff. I ran my graphene without if for a while and could get a full week of battery (tho that was also way more minimalistic app set up)
Pretty much, but GPS being a centralized place to manage notifications also uses a lot of battery. Before I added it I was just using Signal as the APK. On its own it will use a lot of battery checking for new messages. But you can turn that off and just check for messages when you open the app. In that case the phone is effectively only on standby and does not draw much power. I am running a pixel 7 if it matters. I suppose one might also have to self inventory if they care about getting notifications as they come. I certainly do. Still I got the GPS as I was going to be using a few other apps that required them. From a certain perspective I wouldn’t mind being unreachable until i decide to check the app myself. To be clear now that I do use GPS the power draw is similar to when I had a note 9, so it does not seem that the “extra” power use is due to some un-optimized stuff; just that I am in fact running more stuff as one should expect by installing the sandbox.