I agree with the choice of AMD CPU over Intel, it's a no brainer. I'm not sure of the 7700XT as a GPU though. The NVIDIA 4070 seems a better choice. Less power (only needs an 8 pin connector) and it's recently had a price drop.
Gaming laptops are portable in that you can easily move them around. They aren't meant to be used for any length of time without being plugged in. It's made worse by the fact battery technology hasn't kept up with power hungry hardware, apps and bloatware like MS Windows.. 2-3 hours seems...
Starfield seems set to become the latest "will it run Crysis" meme. It's brutal on GPUs and I'll be interested in the CPU requirements given BGS games are notoriously greedy in that area.
Fun game to play though, just dial down the settings on your laptop, probably medium at best.
The OTP gets sent on dispatch, not on delivery day (unless it's same day). You will need to contact PCS and ask them the procedure at their end. It's quite likely they've come across it before.