Fede, I don't disagree with you. I am honored that someone thinks enough of me that they made the effort to gift me something "Buddhisty". But it does put me in an awkward position: telling the person Hotei is not really Buddha would feel ungrateful and might embarrass the giver, but not saying something perpetuates misconceptions.
Mahayana art is often very beautiful. If it were me, I'd keep the calendar or regift it to someone.
"As I am, so are others;
as others are, so am I."
Having thus identified self and others,
harm no one nor have them harmed.
Sutta Nipāta 3.710