LONDON — King Charles III has expressed “deep love and affection” for Australia, a former part of the British Empire. As he visits the country this weekend, he may find that Australians don’t feel quite as much affection for him.

Charles and Queen Camilla arrived Friday evening local time in Sydney, where a tribute on the sails of the city’s iconic opera house displayed a four-minute montage of images from previous royal visits.

Charles, 75, is Britain’s first reigning monarch to…