Home Assistant is strange. You can't install it "normally" on a Pi because Python is too old (it wants 3.8, Raspbian has 3.7). You can install it via Docker but then you can't use Add-Ons. If you want full functionality you're really left with one choice - install their entire OS image on a dedicated Pi. For a collection of Python scripts.

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Fosstodon is an English speaking Mastodon instance that is open to anyone who is interested in technology; particularly free & open source software.