I bought the Aranet4 a while ago, and that seems to meet all your requirements. Keeps measurement history local, but can be paired via Bluetooth (with a pairing

I bought the Aranet4 a while ago, and that seems to meet all your requirements. Keeps measurement history local, but can be paired via Bluetooth (with a pairing code) through their (somewhat flaky) app or open source options. Has a hardware switch to disable Bluetooth. Good quality sensor. Very good battery live due to e-ink screen. Looks pretty neat as well. Quite expensive though, but almost every quality sensor is.