Sounds nice, I hope it will also work properly via Wear OS.

Interesting! Do they support Android Auto?

I used aodNotify by Jawomo quite a time, it is great. (Make sure to use the correct one for your device).

I’m not using it anymore now, because I got a smart watch, which I find more useful for notifications now.

In German we basically use Akku vs Batterie.
As an engineer, I like that distinction, but in English there is no such general clear distinction in every day language (is colloquial the right translation for this?) as far as I know.

Accumulator / Rechargeable battery

as opposed to “regular” one-use battery

Nice, I do something similar for my main phone, with the charger at my work place :)

You could improve the battery life by chaning the automation to charge when below 20% and stop charging at 80%. That way the battery is always between these percentages which apparently is best for it’s health.

Also deliberately using a slow charger for that setup is also a good idea.

https://www.wired.com/story/how-to-improve-battery-life-tips-myths-smartphones/

Some words of caution:

• For anything internet related: Keep in mind that you likely are not getting any security updates anymore, even on a custom ROM.

• Also keep in mind that each accu you have in your home rises the risk of fire slightly. Obviously it always depends on the type and age of each accu.

Now some ideas

• Someone on Lemmy wrote about using a phone as Home Assistant box, but I don’t remember if it was usable enough (e.g. possible to access usb/sensors/etc)

• You might use them as sensors for Home Assistant, however the accu might not last that long, and/or having them connected to power might not be great for the accu

• Run a media center on it (e.g. Kodi) and cast it to your TV

• Connect some speakers and use them as Spotify boxes in different parts of the house (as it is specifically easy switching devices with Spotify. Maybe there is software for general WiFi speakers)

• Use one to create a smart mirror that displays current information like weather etc

Maybe one of those?

(Note: I didn’t try any of these myself.)

• Draw on Photo
• Annotium
• Squid
• iMarkup
• For more, search the Play store with photo note draw

Not sure if they have too many features for your preference.

And what if, after the sync above, I unsub from A on one account and unsub on B plus sub on E on the second account? Both accounts will have C, D and E subbed, right?

Is it possible via the API to get the date/time when a subscription was added? If so, then a two-way sync would be possible, else I think only a one-way sync can be realised reliably, right?