it has very little to do with parties

It has everything to do with sticking to the rules that the government put in place for everyone else:- "Do as I say, not as I do!".

We may be out of lockdown but the pandemic hasn't gone away. If things take a turn for the worse and lockdown has to be reimposed, who is going to listen to Boris? He has lost his authority on the subject.

If he didn't realise that he was breaking his own rules, he is incompetent. If he did, he knowingly misled Parliament. In either case, he should go. His replacement can deal with the situation in Ukraine.

DC