Yes, you can connect this connected watch to a Redmi device, as it's compatible with Android.
Redmi devices run Android, and the Huawei Health app allows pairing with any Android phone, including Xiaomi/Redmi models.
For a watch with the same options (health tracking like sleep, heart rate, SpO2, stress, cycle; activities like running, cycling, fitness; calls, weather, etc.) and native compatibility with your Redmi, check out the Redmi Watch (like the Watch 5 or 6), which run on a proprietary system optimised for Xiaomi.
The case of the Watch GT6 Pro (46 mm) is made of titanium with sapphire glass on the front and a ceramic back.
A metal bracelet is not only available for the "light-coloured" version, but is also available as a separate variant depending on the model.
The metal bracelet is also made of titanium alloy.
Concerning the crown, this is a component that is constantly in use. It may be defective (under warranty). If you're not sure, it would be a good idea to have it checked. As far as Bluetooth on the iPhone is concerned, it seems justified to me that the watch should try to reconnect itself to the iPhone. If the distance is too great or there's no Bluetooth, it seems to work in degraded mode. As soon as it reconnects, it will synchonise and resume its normal functions. I've also been told that you need to keep the Health application activated at all times. This is not the case on Android.
Yes, the ECG can be recorded during exercise. To do this, press the side button during an activity and place a finger on the electrode. The measurement takes about 30 seconds and works independently of the sport mode.
The ECG can be recorded in full. A single-channel ECG is created within 30 seconds, which you can save directly on the watch. The ECG report is saved in the HUAWEI Health app and can be sent from there to your cardiologist by email, for example.
The watch does not support a physical SIM or eSIM, but connects to the smartphone via Bluetooth. It has Bluetooth 6.0 and NFC, but no mobile phone function for a separate SIM or eSIM. The connection to Android and iOS devices is wireless via Bluetooth.