App needs to be restarted
PhoneLeash should work in the background on its own, and automatically start after reboots.
Some phones shutdown background applications to save power, so if you find you need to relaunch PhoneLeash periodically, check if you have power-saving mode turned on. A good article on this: https://www.androidpolice.com/2020/05/30/how-to-prevent-apps-sleeping-in-the-background-on-android/
You should also look for any power save settings for long running background apps and set it to not suspend PhoneLeash.