I have seen this requested in the community previously and I would like to see this option too - there is a bit of a workaround however, if you use a voice assistant, like Amazon Alexa.
Goto routines in the Alexa App and setup a routine to execute an Alexa instruction daily, at a time of your preference and have Alex say the following:
“Alexa, switch on Night Mode on Living Room” where ‘Living Room’ is the name of your Sonos Home Theatre room… the instruction will execute at the time chosen and ‘night mode’ will enable immediately. (NB:You may need another Alexa device in the room to give/receive the instruction).
See my Amazon Alexa Routine screenshot attached.
That is great! Thank you for the tip. Will try to implement this workaround for the time being.