UI is way too small on 4K

The whole UI framework in Unity works per-pixel which makes it hard to scale like this.

Isn't there some functionality in the OS that lets you run a game at blown-up resolution? I do this with various programs in Win10 on my new laptop because the pixels are so tiny.

Yeah, it won't be as sharp as it could be but it'll be nice and playable and just as good as it was designed for.

I have read that Tynan is going to add UI scaling in A16 so try it again.

In my case its in 1080 but I want the UI bigger. I like to not to have to focus my eye on something to check it and avoid having to get closer to the screen sometimes to read a paragraph.

Here's a picture showing how small the UI is: http://i.imgur.com/oAdaZpE.jpg

Tynan is aware of this as its been raised a few times on the forums, theres been no talk but I would expect some UI polish in future alphas which may address this, but youll need Tynan himself to confirm that.

Do you have text scaling enabled on your operating system? Maybe that affect the UI?

Try using 1440p. Way better scale for the UI than 4k.