The Cremator
Spalovač mrtvol (original)
Set in World War II, a demented cremator believes cremation relieves earthly suffering and sets out to save the world.
Starring Rudolf Hrušínský, Vlasta Chramostová, Jana Stehnová, Miloš Vognič, Ilja Prachař, Zora Božinová, Eduard Kohout, Jiří Lír, Dimitri Rafalsky, Jan Vlček
Watch "The Cremator" from streaming services Criterion Channel, Kanopy released in 1969. It's a drama and comedy movie, and has a rating of 8 out of 10 from Imdb which is usually fine for this kind of movie.