I see this as two different things.
1. There's a plot to oust him, as often happens in Westminster politics. But as far as I can tell, the story about parties turned out to be piffling from the perspective of his own involvement.
2. The general public is on the side of taking covid precautions. But a lot of people in his own party have had enough of lockdowns. So that makes things hard.
More generally, the attack on his competence misses the forest for the trees. He did very well on Brexit, wonderfully well on vaccines and the economy is recovering. So he's done well on big ticket items. But he seems to have fewer friends than he needs at the moment.