you can display values or text from loxone but you need different types of outputs: up to 4 objects are cycled through in the information/standby menu, and these are specified using state elements 1 to 4 in the ETS configuration of your glass switch
1) temperature - set the information screen in ETS to show 1 of the 4 elements as type state value 1, and in state value 1 configure this as temperature (it will set data type 9, with a preset text as degC, and you can add a label such as 'outside'
add a group address to the new item in group object
create a standard group actuator with the same address and set it to EIS type 5, set the actuator to send regularly eg 2 or 5 mins to auto update the display
link your temperature in loxone to the EIS actuator
2) for text messages - set 1 of the state elements to state text 1 (over object 120) - there is also a 2nd message state text 2 over object 121 if needed.
these are 14 bytes long and will be trunkated if your message is too long
add group addresses to the state text 1 object (and state text 2 if required)
create a knx text actuator in loxone and give it the matching group address
create a state object in loxone and configure it so your different values or inputs create state-text outputs that contain your message
connect the TQ text output of the state object to your knx text actuator