My present secondary monitor is a wall mounted (same spot) 24" widescreen display mounted with the long axis vertical (so the input is rotated to match) which gives me 1680 vertical. This works for pages I want to screenshot but are often extend below the bottom of my primary screen (many a web page invoice, for example). But, then I give up width, and width is handy for side by side viewing of documents, viewing spreadsheets, and so on.
As far as text goes, the 1050h x 1680v pixel resolution on the present 24" secondary monitor isn't "bad".
It is very individual but the real difference between not too good and how is it going to be in the end is dismal on small monitor.
If you want real 4k you still need a video card supporting the resolution, which your card isn’t.