I've concluded that Badenoch wasn't annoyed that Starmer missed PMQs (particularly given her record), she was annoyed Stride and Philp got their turn in the sun - or more to the point a bit more coverage on Twitter.
I understand Jenrick is the front runner to take over from her but I imagine Stride, Cleverly, Trott and Philp will all throw their hats into the ring when the time comes.
PMs missing PMQs for international summits is entirely to be expected. Sunak missed a number for just that reason.