@medianewbie and @Saucery I don't think anyone on this thread is suggesting Sunak is ND. Possibly they are elsewhere. As you say it seems unlikely - I would expect an autistic person in particular to take quite a serious view of commemorating a serious event respectfully and not diverging from the formal rules around that.
I think a lot of us find him weird but explicitly not ND. Maybe just really out of touch due to privilege. Maybe something else like a personality disorder.
I've also seen the point made on Twitter that being statesman like at major events like this is meant to be one of the best bits of the job and its his last chance to do it. If he doesn't want to do this why did he even want to be PM? Even if he's a rabid narcissist that's puzzling. For all their faults Johnson, Truss and Cameron would have shown up for this - indeed Cameron did.