KORG Keystage

Not a good choice if buying specifically for Pianoteq as your main keyboard?
The polyphonic aftertouch is an excellent feature for synths though. It's far better than mono AT and far better than the dreadful attempt to offer it on CME X Key.
The tiny OLED displays all look pleasantly crisp enough if very, very small.

The synth action keys are fine as a 2nd or third controller in a synth setup. The main keys you want a keyboard with graded hammer action, optimally 88 keys.
The velocity sensitivity of Korg Keystage isn't responsive enough.
If you wish to plonk it on top of another larger hammer action controller or digital piano then it will make a fine addition for multiple layers, if you want those polyphonic aftertouch keys, pitch and modulation and maybe transport controls etc etc?