Ugh, I got lovely light-weight notifications working via either mobile firefox or chrome with https://github.com/jcreedcmu/notifier/ but then it seems like both firefox and chrome have made it impossible to have these notifications cause vibration. Which was exactly what I wanted to make it possible for things happening on the desktop to actually let me know asynchronously when I step away from the computer...
GitHub - jcreedcmu/notifier: Simple notification PWA

Simple notification PWA. Contribute to jcreedcmu/notifier development by creating an account on GitHub.

GitHub
ok, I managed to make a minimal native android app with 'capacitor', which is apparently the spiritual descendant of 'cordova'. Reminds me how much pain java development always seems to entail. Nonetheless it works and I can get vibration on notifications, even.