I wouldn't be worried about buying AMD in terms of thermals, their laptop CPUs are fine. Usually, it's the WiFi card that poses the biggest problem in terms of driver availability, in which case you can purchase an Intel WiFi card from Amazon for $15-$20. Battery and "optimizations" depend on your config and distro. Most plug-and-play distros should be fine OOTB, if you're setting up Arch from scratch I assume you don't have a problem in looking for drivers/compiling code.
Edit: I personally do not suggest that anyone buys a new laptop unless they do not have a choice (horrible used market or the like). There is a heavy mark-up on new devices and the used market in the West (especially in the US) is excellent if you're OK with fiddling with some parts of your laptop (or not - sometimes you don't even need to do that). But being in c/linux that's about granted, eh?
Great link, but OP is looking for an archive solution. I was looking for a self-hosted reddit client so great find!