App Throttler is an open-source Android app that makes the network misbehave for the apps you pick, while the rest of the phone stays untouched. Set download, upload, latency, jitter and packet loss, or load a preset from 2G to Satellite, and tweak them live. Watch every connection, block hosts in one tap, and export .pcap for Wireshark. Scriptable via adb. Runs as a local VPN, and doesn't require your device to be rooted.