This is important, but sadly a lot of people don't seem to notice/care what Google is doing to Android. The question in my mind is whether the quality of devices like the Pinephone can get high enough before the functionality of Android drops below a point where certain things simply become impossible.

Sadly true, indeed.

It's a shame we're losing so much useful functionality there.

Security is a worthy goal but getting rid of useful features just because Google wants to handhold Android users so much seems to me like throwing out the baby with the bathwater.

I was using SL4A [0] back in the days, had a Twisted server running on it, until the development on it stopped.

[0] https://en.wikipedia.org/wiki/Scripting_Layer_for_Android

You should have a look at Python-for-Android, it's maintained and works quite well.

https://python-for-android.readthedocs.io

"Linux Phone"... music to my ears!