MacOS: check out the
latest MacBook Air 13", the one just released - it has a new keyboard, better base disk configuration and it's cheaper than before.
Windows: Dell XPS 13 has been the go-to laptop for years, they keep refreshing it, so make sure to get at least the 2019 model (which has a camera on the top of the screen, not the bottom), or ideally the 2020 model, which features a new keyboard and even smaller bezels (and a new, 16:10 screen).
Windows runner up: look at Surface Pro 7 (x86) and Pro X (ARM), if the form factor, performance and ergonomics fit your needs, they might be preferable to the XPS 13. The Pro X is quite a wild card, since the compatibility is not quite there yet, but it's closer to a paper notebook than laptops or even the Pro 7.
I would advise against anything smaller than 13", because it will be fairly suboptimal to type on.