"- buggy Android compatibility and near zero native devs, all jumped ship"

I'm a bit confused by this. Are you saying that the developers who once wrote native Sailfish OS apps are no longer writing those native apps?

Is there any hope for using the responsive libadwaita programs from the Mobile Linux space? I realise this isn't particularly large, but it is active.

> Is there any hope for using the responsive libadwaita programs from the Mobile Linux space?

Currently not, if I understand correctly. There are plans to update or rewrite the Wayland compositor. If all goes well it should support GTK programs and I assume libadwaita too.