Hello Valerio, I have added some variables on https://meta.wikimedia.org/wiki/Template:Cronos_event
In order to manage event on multiple days, I'm thinking about using the variable

end

for both end time and date for example 2019-05-14 14:00

when

variable will be the starting time only
What do you think ?
Feel free to add infos on https://meta.wikimedia.org/wiki/Meta:Wikimedia_CH/Meta:Cronos#Variables_name_table