Given the current state of partisan polarization, it’s unlikely Biden can get majority job approval next year even with the most fortunate set of circumstances. But the good news for him is that he probably doesn’t have to. Job-approval ratings are crucial indicators in a normal presidential reelection cycle that is basically a referendum on the incumbent’s record. Assuming Trump is the Republican nominee, 2024 will not be a normal reelection cycle for three reasons.
He also said “with all her mistakes and total lack of charisma”. It read, to me at least, as anti-Trump and not pro-Clinton. (Even a bit anti-Clinton, as defending someone by saying they have no Charisma is… a weird way of going about it at least.)