Yes, the charger is included in the scope of delivery. The scope of delivery includes a size-specific charger and a USB-C cable, but not a power adapter, which must be connected separately to a power source.
The ring size is 4. This size is part of the available range for this smart ring, which comes in sizes 4 to 15 without half sizes. The sizing is specific to this generation and differs from previous models, so using the correct sizing kit is recommended for an accurate fit. The ring weighs approximately 5.20 grams and is made of metal with a pink gold colour.
The QR code is displayed in the instructions for use and refers you to the Oura app (you can also find it yourself in the store). After a free trial month, you can then start your membership as a monthly or annual fee. Everything is simple and straightforward.
Since your ideal size is 7.5, I recommend choosing a size 7. This fits well with cool hands and will not be too loose with warm hands as your fingers will expand slightly. A tighter fit will prevent the ring from being too loose, making it easier to take accurate measurements and prevent slippage.