Scrcpy

[Don B. Cilly]

Well, I gave up on network. I dislike the idea of having my phone connected via USB depending on the whims of software, but I sort of found a workaround.
I use an oldish crapphone with a pretty much shot battery. Have that run the app I want to monitor. Bob's my uncle.
Stays connected to USB, runs the app, I monitor it from over here.

I tried to use Airdroid for it. Useless. Scrcpy is good. Wakes up the phone screen, pretty much no latency... great

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[Don B. Cilly]

Well, just for general (dis)interest, I got it working over wifi. The procedure is:
Connect USB cable
adb tcpip 5555
Disconnect USB cable
adb connect <IP address>:5555

Response time/latency over network is definitely slower than over USB (which is pretty much instant).
If you restart the phone or the computer, you have to repeat the above procedure.