Its standard... Higher resolution but same resolution interface means your interface looks a lot smaller. A 10 pixel wide image will look much smaller on a 2000pixel wide monitor than on a 1000 pixel wide monitor.
Emps doesn't have custom interface scaling, best way to 'fix' it or atleast display bigger is to set your resolution smaller on your monitor but that would defeat the purpose of a 4k monitor because youre not displaying at 4k.
If you buy a monitor that is 2x the resolution of what you had, you either buy 2x the inches wide size or youre stuck with smaller interfaces
example:
conclusion: dont buy expensive shit with newer standards without the time being ready for it/you not knowing what it means. Our programs of today are optimized for 2k resolution and itll take a while before everything will be adjusted for 4k resolution screens