Something that I know many of us do when we install KDE and configure it is precisely this, remove the events, holidays that the calendar shows us:
To indicate that we do not want to see these events (since we only want to see the days and months) we must right-click on the panel clock:
The detail is that this alone was not enough for me at least, in my case I also had to look in the Select column for the one that said Days off or Information, because it was useless to uncheck before showing events, if I did not change where said Information or Days off to Not used, then events would simply continue to show:
Once everything is set to Not used, it is a matter of accepting the changes and voila, we will have the calendar without showing dates or holidays.
Anyway, nothing more to add, this may seem something too simple but I know that I am not the only one who wanted to remove the events and KDE did not pay attention to it 😀