I have a somewhat rugged chromebook(Asus C201), which is not waterproof, but quite waterresistant and still with a decent keyboard. I used it while backpacking

I have a somewhat rugged chromebook(Asus C201), which is not waterproof, but quite waterresistant and still with a decent keyboard. I used it while backpacking in rough areas and it got wet and sandy and got dropped in wet dirt - but never had an issue with typing. So I think it is possible to get a good balance of waterproof and ergonomic keyboard. But full waterproof would be probably indeed hard.