I want to add some kind of display to be able to control/view HA in my kitchen. I already have HA running on my server, and am looking to buy an portable 13.3/15.6 touchscreen monitor for this. I already have a cuple of raspberry pi zero 2 w that I am not using. Would it be possible to use a RPI Zero 2 W for displaying and controling HA ? What OS is recommended in that case ?
Install Raspberry Pi OS desktop lite, add a HDMI cable and display, and test of the browser is good enough for your needs. It will be slow.
If so, get a touch screen.
The official flash tool also includes OS options like kiosk mode for browser only displays. I sometimes add buttons to the GPIO for specific actions or shutdown, but have used RPi3 for GUI displays.
RPi Zero are useful for more complex automations, such as with a Pimproni hat - e.g. Grow, Enviro, etc.
I have a modified Python module for Grow which used MQTT for HASS.