The only option if a native 1440p 27" display (2540 x 1440, but tack sharp compared to 4K scaling)
Only if you habitually view your screen from 2 inches away through a jeweller’s loupe, and think being able discern individual pixels is somehow “sharper” than seeing a bit of anti-aliasing.
“Looks like 2560x1440” on a 4K display is actually 5k downsampled to 4K, and as such contains a lot more detail than a native 2560x1440 screen. You might get a performance hit if you’re using a Mac with a weak GPU (I’d worry about the Mac Mini) but a decent GPU with its own RAM won’t struggle.
Plus, you get the flexibility of having “looks like” 1080p mode (which is full 4K with double-sized system text and icons) or 1:1 4K (if you’re using a full screen app with its own scaling, a game, 4K video etc.)
You won’t have that flexibility on a 1440p native display - anything other than native 1440p will look very rough.
However, following your comments I am now looking at 2540 x 1440 display.
That might be a good choice if it suits your needs - but not because it will be “better” than a 4K display in scaled mode - it isn’t*.
(* unless you push the boat out on a pro 1440p display from Eizo or suchlike which may have better colour
reproduction and calibration facilities - and probably a higher price tag - than a cheap 4K - but that’s probably irrelevant unless your a graphics pro who is going to run a colour-calibrated workflow and trade resolution for colour accuracy).