Building an offline smart home using Home Assistant is signing yourself to an unpaid SRE and nobody at home appreciate your work, it maybe a fun activity but don't expect too much out of it.

I did about 20% of the article's setup which took about a weekend of time, then randomly after Home Assistant update certain things start not functioning, i.e. I bought some $2 Xiaomi BLE temperature sensors and the key I setup just somehow stopped working, then its another half day wasted on trouble shooting them.

I regret my time wasted on them, especially given Home Assistant's data retention is not as great as I was expecting, i.e. default storage is only 14 days for temperature sensor and that sqlite DB is huge with this limited data.