I’ve done similar with an old Android tablet. Installed Fully Kiosk Browser to display the dashboard AND read the battery level - above 75%, switch off power…
But… automations only trigger when going past the threshold once, so if there’s a random issue where HA doesn’t see the battery drop below 10%, (had that happen a few times in the past), then I also have multiple triggers for 5% and 2%… to turn the power back on again 😉
Just on your Enlightenment point there, I tried Bodhi Linux a few years ago because the Enlightenment desktop looked really good, but over time they (Bodhi) had to create their own desktop because Enlightenment appeared to have almost stopped work.
Might be something for you to check out…?