In 2017 Kim didn't show up with his leaders either, rather paid tribute a couple days later by himself and photographed......However it's believed, Kim wants to break away from the past, as well as the North's traditional cult of personality and brand himself as a leader who is modern and competent, rather than a descendant of his predecessors...and it's said his absence is unrelated to coronavirus because he's been quite active in recent weeks.
Here's The ruling party without Kim 4/16/2020