Looking at France panicking because 2 weeks after snap election there isn’t a clear majority, nor a coalition ready to propose a prime-minister to the president. What would be the standard time to do these negotiations in a functional democracy where doing coalition is common but doesn’t take years (so US and Belgium do not coun :) )
EDIT : Need not Name
In Germany there is no official limit for how long it can take to form a new government. If there is no clear winner and the coalition talks are complicated, it can easily take a month or more. After the election in 2017 it took almost half a year before Merkel was elected as Chancellor and the government was formed. That was uncommonly long though.
For the time between the first sitting of the newly elected parliament (30 days after the election iirc) and the formation of a new government the previous government acts as caretaker government.