To be fair Dave, Corbyn wished the Queen a happy birthday a few years ago when asked if he was a Republican. He deflected the question knowing he would get slaughtered if said anything even remotely anti-monarchy. Corbyn, like myself, is an ardent Republican, but sometimes you have to tread carefully.
That said, Starmer should be blitzing the government over lack of PPE, the effects of austerity and Thatcherism on the NHS and the lack of an industrial place to produce much needed items like ventilators and PPE.