Comment by afarah1

>I want software that doesn't send anything to the Internet without some explicit intent first.

I too want exactly that, which got me thinking, that's what firewalls are for! DROP OUTBOUND by default, explicit allow per-app.

On Andoid, iptables-based firewalls require root, which wasn't a good option for me (no twrp support for my device), so after some searching I stumbled upon NetGuard - open source and rootless, implements a firewall using Android's VPN service (you can configure Android to route all traffic through this "VPN" which is actually a local firewall). The downside is you can't use an actual VPN (except with some complicated setup involving work profiles and other apps). I've been using it for a couple of weeks and am very satisfied, I noticed apps phoning home which I did not want to, like a scanning app I had used to scan private documents in the past, perhaps an oversight on my part.