I've delved into the rabbit hole of privacy-preserving home monitoring equipment so might as well write it down for whoever plans to be the same thing.
My original intent was to have an offline clock that provides humidity and temperature; however, one thing led to another - wine cellar, fermentation chamber, or wardrobe where you keep your precious Kashmir.
There is an open-sourced project:
https://github.com/home-assistant/
And supported device list like this where you can buy from Amazon for cheap:
https://www.home-assistant.io/integrations/govee_ble/
You don't even need to audit the manufacturer's app as you won't be needing them.