Boris will survive no matter how many resignations there are at the moment.
If a GE is called now Boris will still survive, that’s because the alternative (opposition) is unthinkable and they can’t really make the situation better no matter how much they try.
However, with the way the world is going Boris might be weaken but his main test will come in two years time. If Conservative plays the ball right they will still be in power but that will depend if Labour or the oppositions will “bride” the population to vote for them by promising the sky (they usually do).
The oppositions are making the loudest noise at the moment but they will not win the next GE. Compare their leaders to Boris the are merely different sides of the same coin.
Angela Rayner for PM? That will learn you.
p/s: also if I were Scottish I would rather face a Conservative government rather than a Labour government …