In Australia I’ve found that people in general here are indifferent to the monarchy/BRF, though there were high ratings for the Oprah interview, so perhaps dramatic events appeal. I’ve been here decades and interest in the BRF in particular has definitely faded, though the Queen still garners respect.
I I think it’s the same in Britain, except perhaps for Jubilee holidays, just an all over fading into indifference towards most of them. And sorry, but I wouldn’t say Charles and Camilla are popular in either country. The aftermath of the Diana years still remains with many people, and most under-40s wouldn’t be able to name many members of the BRF, here in Australia anyway.