The Xposed module. Make your app debuggable=true on the fly.
Tested on Nougat 7.1.2, may work with any Android 6.0+ & Xposed.
This module hook the app picker for debug in Developer Settings to make any app appears even without debuggable=true in their manifest and ROM marked as release (or any kind of stock rom). Meanwhile, It hooked Zygote to start the app (selected above) process with certain debug flag so that only selected app will start with debug server. This avoid the may-have overhead(opposite to XInstaller).
This module have NO user interface. Just install and activate in Xposed Installer then it worked. You can found a prebuilt version at releases page.