Depends, Cubase and it’s lower zones are ok but not on the level of other daws like ableton/bitwig which are more laptop/small screen friendly. Cubase is still old school windows based and its more designed like that(which I personally prefer) the other important thing is scaling which cubase cannot be proud of and probably will pass many years till its get properly. So I advise don’t think about 4k on anything bellow 43"
2K is surely good, I have 34 ultrawide (3440x1440) and its ok, I am not far away from it but some things are tiny and its a inch to go on scaling 
I am fine with horizontal res, but often I need that vertical space (more than 1440) where on 4k you don’t have any struggle. But using Cubase’s workspaces make that way less annoying.
Idk what 52" 4k you have but working in 4k and have optimal distance from screen is way enjoyable than on 2k. Especially if you have busy projects with many channels.
Here is nice topic on the 4k subject: