Does it heat up while sleeping? (I may be in the market for a new machine, but reports of laptops cooking themselves on "modern standby" are... off-putting
No. It works fine. I put my computer to sleep rather than turning it off usually, sometimes unplugged. My bios is up to date (fwupd can be used to update it). You need to leave the Linux S3 mode disabled in the BIOS though, it's broken (or maybe they fixed it, but I haven't tried recently, the "modern standby" seems to work correctly on Linux now, at least on my machines)