Large UI needed for 4k monitors.

Could you post some screenshots? I'd like to see what you're talking about and it might help the devs as well.

Are you talking a games option settings, or this actual website.  Sorry for asking.  It's just something about the way you've written your post is making me think you're talking about a game.  If you're talking about a game, like Endless Space 2, then you need to put it in ES2's ideas section.  Here:

https://www.games2gether.com/endless-space-2/ideas/

If you put it there, I will up-vote it as well, because I would very much like proper 4k scaling in ES2 as well.  If you are talking about the website, you need to use the scaling options with windows or your bowser instead, because the websites scaling is just fine.  If on windows 10, go to Start -> Settings -> System -> Display Section, and move the slider to increase text and icon scaling.  I run my 4k monitor at 150% scaling.  If you just need it in your browser, then it's an even simpler fix.  Simply hold down the ctrl key on your keyboard and scroll your mouse wheel up and down until you get your desired scaling.  This works with pretty much every browser, I think.

Hope this helps.