Quite a lot of work went into your program, I bet you learned some good code while writing it. I’ve used a simple Windows program called Easy Net Monitor. You can specify IP address or hostname connectivity tracking with email alerts.
I seek out phones with audio jacks. My current Moto G Power 2020 has one and I use it all the time. No dongles or adapters in the car or on various headphones. Plus I actually use the FM Radio built into the phone and that uses the wire for the headphones as an antenna. I just cut off some old earbuds and plug that in, then direct the audio to either the phone speaker itself or BT.
Correct, if that machine goes down you won’t have any notification. I was thinking along the lines of you are hosting services on one machine while the computer itself is acting as the host or hypervisor.